diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5f74d29ff3a1..26b22e9aaf8b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -329,7 +329,7 @@ these optimizations.
 - Return early where possible in subtype check (Stanislav Terliakov, PR [19400](https://github.com/python/mypy/pull/19400))
 - Deduplicate some types before joining (Stanislav Terliakov, PR [19409](https://github.com/python/mypy/pull/19409))
 - Speed up type checking by caching argument inference context (Jukka Lehtosalo, PR [19323](https://github.com/python/mypy/pull/19323))
-- Optimize binding method self argument type and deprecation checks (Ivan Levkivskyi, PR [19556](https://github.com/python/mypy/pull/19556))
+- Optimize binding method self parameter type and deprecation checks (Ivan Levkivskyi, PR [19556](https://github.com/python/mypy/pull/19556))
 - Keep trivial instance types/aliases during expansion (Ivan Levkivskyi, PR [19543](https://github.com/python/mypy/pull/19543))
 
 ### Fixed‑Format Cache (Experimental)
diff --git a/docs/source/error_code_list2.rst b/docs/source/error_code_list2.rst
index 36cf05d4f3f8..5008ef2ff997 100644
--- a/docs/source/error_code_list2.rst
+++ b/docs/source/error_code_list2.rst
@@ -94,7 +94,7 @@ Check that methods do not have redundant Self annotations [redundant-self]
 --------------------------------------------------------------------------
 
 If a method uses the ``Self`` type in the return type or the type of a
-non-self argument, there is no need to annotate the ``self`` argument
+non-self parameter, there is no need to annotate the ``self`` parameter
 explicitly. Such annotations are allowed by :pep:`673` but are
 redundant. If you enable this error code, mypy will generate an error if
 there is a redundant ``Self`` type.
diff --git a/docs/source/more_types.rst b/docs/source/more_types.rst
index 0383c3448d06..94c1aafff667 100644
--- a/docs/source/more_types.rst
+++ b/docs/source/more_types.rst
@@ -729,7 +729,7 @@ for certain values of type arguments (Python 3.12 syntax):
            return self.item.upper()
 
    def label(ti: Tag[int], ts: Tag[str]) -> None:
-       ti.uppercase_item()  # E: Invalid self argument "Tag[int]" to attribute function
+       ti.uppercase_item()  # E: Invalid self parameter "Tag[int]" to attribute function
                             # "uppercase_item" with type "Callable[[Tag[str]], str]"
        ts.uppercase_item()  # This is OK
 
@@ -750,7 +750,7 @@ argument is itself generic (Python 3.12 syntax):
    page: Storage[list[str]]
    page.first_chunk()  # OK, type is "str"
 
-   Storage(0).first_chunk()  # Error: Invalid self argument "Storage[int]" to attribute function
+   Storage(0).first_chunk()  # Error: Invalid self parameter "Storage[int]" to attribute function
                              # "first_chunk" with type "Callable[[Storage[Sequence[S]]], S]"
 
 Finally, one can use overloads on self-type to express precise types of
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index c04f0bd2b4fa..bd7e7d06ec34 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -5695,7 +5695,7 @@ def _super_arg_types(self, e: SuperExpr) -> Type | tuple[Type, Type]:
             current_type = fill_typevars(e.info)
             type_type: ProperType = TypeType(current_type)
 
-            # Use the type of the self argument, in case it was annotated
+            # Use the type of the self parameter, in case it was annotated
             method = self.chk.scope.current_function()
             assert method is not None
             if method.arguments:
diff --git a/mypy/messages.py b/mypy/messages.py
index 03062a9d3de4..8ca3eb071c67 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -1459,7 +1459,7 @@ def cannot_determine_type_in_base(self, name: str, base: str, context: Context)
     def no_formal_self(self, name: str, item: CallableType, context: Context) -> None:
         type = format_type(item, self.options)
         self.fail(
-            f'Attribute function "{name}" with type {type} does not accept self argument', context
+            f'Attribute function "{name}" with type {type} does not accept self parameter', context
         )
 
     def incompatible_self_argument(
@@ -1469,7 +1469,7 @@ def incompatible_self_argument(
         arg_type = format_type(arg, self.options)
         sig_type = format_type(sig, self.options)
         self.fail(
-            f'Invalid self argument {arg_type} to {kind} "{name}" with type {sig_type}', context
+            f'Invalid self parameter {arg_type} to {kind} "{name}" with type {sig_type}', context
         )
 
     def incompatible_conditional_function_def(
diff --git a/mypy/plugins/attrs.py b/mypy/plugins/attrs.py
index 617ae8eb83a6..72144901bde5 100644
--- a/mypy/plugins/attrs.py
+++ b/mypy/plugins/attrs.py
@@ -1016,7 +1016,7 @@ def add_method(
     ) -> None:
         """Add a method: def <method_name>(self, <args>) -> <ret_type>): ... to info.
 
-        self_type: The type to use for the self argument or None to use the inferred self type.
+        self_type: The type to use for the self parameter or None to use the inferred self type.
         tvd: If the method is generic these should be the type variables.
         """
         self_type = self_type if self_type is not None else self.self_type
@@ -1090,7 +1090,7 @@ def _get_expanded_attr_types(
             _fail_not_attrs_class(ctx, display_typ, parent_typ)
             return None
         init_func = expand_type_by_instance(init_func, typ)
-        # [1:] to skip the self argument of AttrClass.__init__
+        # [1:] to skip the self parameter of AttrClass.__init__
         field_names = cast(list[str], init_func.arg_names[1:])
         field_types = init_func.arg_types[1:]
         return [dict(zip(field_names, field_types))]
diff --git a/mypyc/irbuild/builder.py b/mypyc/irbuild/builder.py
index 30d117e42c71..e7da257a6365 100644
--- a/mypyc/irbuild/builder.py
+++ b/mypyc/irbuild/builder.py
@@ -1276,7 +1276,7 @@ def enter_method(
         """Generate IR for a method.
 
         If the method takes arguments, you should immediately afterwards call
-        add_argument() for each non-self argument (self is created implicitly).
+        add_argument() for each non-self parameter (self is created implicitly).
 
         Args:
             class_ir: Add method to this class
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index 5a66eff2bd3b..d57702725f9f 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -3339,7 +3339,7 @@ class Test:
         # E: Method must have at least one argument. Did you forget the "self" argument?
 
 t = Test()
-t.crash = 'test'  # E: Attribute function "__setattr__" with type "Callable[[], None]" does not accept self argument \
+t.crash = 'test'  # E: Attribute function "__setattr__" with type "Callable[[], None]" does not accept self parameter \
                   # E: "Test" has no attribute "crash"
 
 class A:
@@ -3574,7 +3574,7 @@ class B:
     a = A
     bad = lambda: 42
 
-B().bad() # E: Attribute function "bad" with type "Callable[[], int]" does not accept self argument
+B().bad() # E: Attribute function "bad" with type "Callable[[], int]" does not accept self parameter
 reveal_type(B.a) # N: Revealed type is "def () -> __main__.A"
 reveal_type(B().a) # N: Revealed type is "def () -> __main__.A"
 reveal_type(B().a()) # N: Revealed type is "__main__.A"
@@ -5286,9 +5286,9 @@ reveal_type(A.g4)  # N: Revealed type is "def () -> def () -> __main__.A"
 class B(metaclass=M):
     def foo(self): pass
 
-B.g1  # E: Invalid self argument "type[B]" to attribute function "g1" with type "Callable[[type[A]], A]"
-B.g2  # E: Invalid self argument "type[B]" to attribute function "g2" with type "Callable[[type[TA]], TA]"
-B.g3  # E: Invalid self argument "type[B]" to attribute function "g3" with type "Callable[[TTA], TTA]"
+B.g1  # E: Invalid self parameter "type[B]" to attribute function "g1" with type "Callable[[type[A]], A]"
+B.g2  # E: Invalid self parameter "type[B]" to attribute function "g2" with type "Callable[[type[TA]], TA]"
+B.g3  # E: Invalid self parameter "type[B]" to attribute function "g3" with type "Callable[[TTA], TTA]"
 reveal_type(B.g4)  # N: Revealed type is "def () -> def () -> __main__.B"
 
 # 4 examples of unsoundness - instantiation, classmethod, staticmethod and ClassVar:
@@ -5301,9 +5301,9 @@ reveal_type(ta.g3)  # N: Revealed type is "def () -> type[__main__.A]"
 reveal_type(ta.g4)  # N: Revealed type is "def () -> type[__main__.A]"
 
 x: M = ta
-x.g1  # E: Invalid self argument "M" to attribute function "g1" with type "Callable[[type[A]], A]"
-x.g2  # E: Invalid self argument "M" to attribute function "g2" with type "Callable[[type[TA]], TA]"
-x.g3  # E: Invalid self argument "M" to attribute function "g3" with type "Callable[[TTA], TTA]"
+x.g1  # E: Invalid self parameter "M" to attribute function "g1" with type "Callable[[type[A]], A]"
+x.g2  # E: Invalid self parameter "M" to attribute function "g2" with type "Callable[[type[TA]], TA]"
+x.g3  # E: Invalid self parameter "M" to attribute function "g3" with type "Callable[[TTA], TTA]"
 reveal_type(x.g4)  # N: Revealed type is "def () -> __main__.M"
 
 def r(ta: Type[TA], tta: TTA) -> None:
@@ -7889,11 +7889,11 @@ reveal_type(A().fn3)  # N: Revealed type is "builtins.int"
 reveal_type(A().fn4)  # N: Revealed type is "builtins.int"
 reveal_type(A().fn5)  # N: Revealed type is "builtins.int"
 
-reveal_type(A().g1)  # E: Attribute function "g1" with type "Callable[[], None]" does not accept self argument \
+reveal_type(A().g1)  # E: Attribute function "g1" with type "Callable[[], None]" does not accept self parameter \
                      # N: Revealed type is "def ()"
-reveal_type(A().g2)  # E: Invalid self argument "A" to attribute function "g2" with type "Callable[[int], None]" \
+reveal_type(A().g2)  # E: Invalid self parameter "A" to attribute function "g2" with type "Callable[[int], None]" \
                      # N: Revealed type is "def ()"
-reveal_type(A().g3)  # E: Invalid self argument "A" to attribute function "g3" with type "Callable[[int], None]" \
+reveal_type(A().g3)  # E: Invalid self parameter "A" to attribute function "g3" with type "Callable[[int], None]" \
                      # N: Revealed type is "def ()"
 [builtins fixtures/tuple.pyi]
 
@@ -7931,7 +7931,7 @@ class A:
         return 0
 
 reveal_type(A().fn1)  # N: Revealed type is "def () -> builtins.int"
-reveal_type(A().fn2)  # E: Invalid self argument "A" to attribute function "fn2" with type "Callable[[int], int]" \
+reveal_type(A().fn2)  # E: Invalid self parameter "A" to attribute function "fn2" with type "Callable[[int], int]" \
                       # N: Revealed type is "def () -> builtins.int"
 reveal_type(A().fn3)  # N: Revealed type is "def (_x: builtins.int) -> builtins.int"
 
@@ -7952,11 +7952,11 @@ class B:
     def fn4(self, new_self: 'B') -> int:
         return 0
 
-reveal_type(B().fn1)  # E: Attribute function "fn1" with type "Callable[[], int]" does not accept self argument \
+reveal_type(B().fn1)  # E: Attribute function "fn1" with type "Callable[[], int]" does not accept self parameter \
                       # N: Revealed type is "def () -> builtins.int"
-reveal_type(B().fn2)  # E: Attribute function "fn2" with type "Callable[[], int]" does not accept self argument \
+reveal_type(B().fn2)  # E: Attribute function "fn2" with type "Callable[[], int]" does not accept self parameter \
                       # N: Revealed type is "def () -> builtins.int"
-reveal_type(B().fn3)  # E: Invalid self argument "B" to attribute function "fn3" with type "Callable[[int], int]" \
+reveal_type(B().fn3)  # E: Invalid self parameter "B" to attribute function "fn3" with type "Callable[[int], int]" \
                       # N: Revealed type is "def () -> builtins.int"
 reveal_type(B().fn4)  # N: Revealed type is "def () -> builtins.int"
 
@@ -7990,11 +7990,11 @@ class D:
     def fn3(self, _x: int) -> int:  # E: "self" parameter missing for a non-static method (or an invalid type for self)
         return 0
 
-reveal_type(D().fn1)  # E: Invalid self argument "D" to attribute function "fn1" with type "Callable[[int], int]" \
+reveal_type(D().fn1)  # E: Invalid self parameter "D" to attribute function "fn1" with type "Callable[[int], int]" \
                       # N: Revealed type is "def () -> builtins.int"
-reveal_type(D().fn2)  # E: Invalid self argument "D" to attribute function "fn2" with type "Callable[[int, int], int]" \
+reveal_type(D().fn2)  # E: Invalid self parameter "D" to attribute function "fn2" with type "Callable[[int, int], int]" \
                       # N: Revealed type is "def (_x: builtins.int) -> builtins.int"
-reveal_type(D().fn3)  # E: Invalid self argument "D" to attribute function "fn3" with type "Callable[[int, D, int], int]" \
+reveal_type(D().fn3)  # E: Invalid self parameter "D" to attribute function "fn3" with type "Callable[[int, D, int], int]" \
                       # N: Revealed type is "def (self: __main__.D, _x: builtins.int) -> builtins.int"
 [builtins fixtures/tuple.pyi]
 
@@ -9360,7 +9360,7 @@ class C(B):
     prop_t = AT.prop  # E: Incompatible types in assignment (expression has type "C", base class "B" defined the type as "str")
 
 reveal_type(C().prop)  # N: Revealed type is "builtins.str"
-C().prop = "no"  # E: Invalid self argument "C" to attribute function "prop" with type "Callable[[A, str], None]"
+C().prop = "no"  # E: Invalid self parameter "C" to attribute function "prop" with type "Callable[[A, str], None]"
 reveal_type(C().prop_t)  # N: Revealed type is "__main__.C"
 C().prop_t = 1  # E: Incompatible types in assignment (expression has type "int", variable has type "list[C]")
 [builtins fixtures/property.pyi]
diff --git a/test-data/unit/check-functions.test b/test-data/unit/check-functions.test
index bff8c03a8fc5..3f2b5c8680ac 100644
--- a/test-data/unit/check-functions.test
+++ b/test-data/unit/check-functions.test
@@ -616,8 +616,8 @@ class A:
     f = x # type: ClassVar[Callable[[], None]]
     g = x # type: ClassVar[Callable[[B], None]]
 a: A
-a.f() # E: Attribute function "f" with type "Callable[[], None]" does not accept self argument
-a.g() # E: Invalid self argument "A" to attribute function "g" with type "Callable[[B], None]"
+a.f() # E: Attribute function "f" with type "Callable[[], None]" does not accept self parameter
+a.g() # E: Invalid self parameter "A" to attribute function "g" with type "Callable[[B], None]"
 
 [case testMethodWithDynamicallyTypedMethodAsDataAttribute]
 from typing import Any, Callable, ClassVar
@@ -692,7 +692,7 @@ class A(Generic[t]):
 ab: A[B]
 ac: A[C]
 ab.f()
-ac.f()   # E: Invalid self argument "A[C]" to attribute function "f" with type "Callable[[A[B]], None]"
+ac.f()   # E: Invalid self parameter "A[C]" to attribute function "f" with type "Callable[[A[B]], None]"
 
 [case testPartiallyTypedSelfInMethodDataAttribute]
 from typing import Any, TypeVar, Generic, Callable, ClassVar
@@ -3686,14 +3686,14 @@ reveal_type(C.x5)  # N: Revealed type is "def (x: builtins.int) -> builtins.str"
 reveal_type(C.x6)  # N: Revealed type is "def (x: builtins.int) -> builtins.str"
 reveal_type(C.x7)  # N: Revealed type is "def (builtins.int) -> builtins.str"
 
-reveal_type(C().x1)  # E: Invalid self argument "C" to attribute function "x1" with type "Callable[[A, int], str]" \
+reveal_type(C().x1)  # E: Invalid self parameter "C" to attribute function "x1" with type "Callable[[A, int], str]" \
                      # N: Revealed type is "def (x: builtins.int) -> builtins.str"
 reveal_type(C().x2)  # N: Revealed type is "def (x: builtins.int) -> builtins.str"
 reveal_type(C().x3)  # N: Revealed type is "def (x: builtins.int) -> builtins.str"
 reveal_type(C().x4)  # N: Revealed type is "def (x: builtins.int) -> builtins.str"
 reveal_type(C().x5)  # N: Revealed type is "def (x: builtins.int) -> builtins.str"
 reveal_type(C().x6)  # N: Revealed type is "def (x: builtins.int) -> builtins.str"
-reveal_type(C().x7)  # E: Invalid self argument "C" to attribute function "x7" with type "Callable[[int], str]" \
+reveal_type(C().x7)  # E: Invalid self parameter "C" to attribute function "x7" with type "Callable[[int], str]" \
                      # N: Revealed type is "def () -> builtins.str"
 [builtins fixtures/classmethod.pyi]
 
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index c15720035256..bf9ff8dd3ef7 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -689,7 +689,7 @@ class C(Generic[T]):
 i: C[int]
 s: C[str]
 
-i.from_item()  # E: Invalid self argument "C[int]" to attribute function "from_item" with type "Callable[[C[str]], None]"
+i.from_item()  # E: Invalid self parameter "C[int]" to attribute function "from_item" with type "Callable[[C[str]], None]"
 s.from_item()
 
 [case testSelfTypeRestrictedClassMethod]
@@ -703,9 +703,9 @@ class C(Generic[T]):
 class DI(C[int]): ...
 class DS(C[str]): ...
 
-DI().from_item()  # E: Invalid self argument "type[DI]" to class attribute function "from_item" with type "Callable[[type[C[str]]], None]"
+DI().from_item()  # E: Invalid self parameter "type[DI]" to class attribute function "from_item" with type "Callable[[type[C[str]]], None]"
 DS().from_item()
-DI.from_item()  # E: Invalid self argument "type[DI]" to attribute function "from_item" with type "Callable[[type[C[str]]], None]"
+DI.from_item()  # E: Invalid self parameter "type[DI]" to attribute function "from_item" with type "Callable[[type[C[str]]], None]"
 DS.from_item()
 [builtins fixtures/classmethod.pyi]
 
@@ -844,7 +844,7 @@ class Sub(Base[List[int]]): ...
 class BadSub(Base[int]): ...
 
 reveal_type(Sub().get_item())  # N: Revealed type is "builtins.int"
-BadSub().get_item()  # E: Invalid self argument "BadSub" to attribute function "get_item" with type "Callable[[Base[list[S]]], S]"
+BadSub().get_item()  # E: Invalid self parameter "BadSub" to attribute function "get_item" with type "Callable[[Base[list[S]]], S]"
 [builtins fixtures/list.pyi]
 
 [case testMixinAllowedWithProtocol]
@@ -871,10 +871,10 @@ class Bad(AtomicClose, Copyable):
 f: File
 b: Bad
 f.atomic_close()  # OK
-b.atomic_close()  # E: Invalid self argument "Bad" to attribute function "atomic_close" with type "Callable[[Resource], int]"
+b.atomic_close()  # E: Invalid self parameter "Bad" to attribute function "atomic_close" with type "Callable[[Resource], int]"
 
 reveal_type(f.copy())  # N: Revealed type is "__main__.File"
-b.copy()  # E: Invalid self argument "Bad" to attribute function "copy" with type "Callable[[T], T]"
+b.copy()  # E: Invalid self parameter "Bad" to attribute function "copy" with type "Callable[[T], T]"
 [builtins fixtures/tuple.pyi]
 
 [case testMixinProtocolSuper]
@@ -912,7 +912,7 @@ class Test:
     def meth(self, x: str) -> int: ...
 
 reveal_type(Test().meth)  # N: Revealed type is "def (x: builtins.str) -> builtins.int"
-Test()._deco  # E: Invalid self argument "Test" to attribute function "_deco" with type "Callable[[F], F]"
+Test()._deco  # E: Invalid self parameter "Test" to attribute function "_deco" with type "Callable[[F], F]"
 [builtins fixtures/tuple.pyi]
 
 [case testSelfTypeTrickyExample]
@@ -973,9 +973,9 @@ T = TypeVar('T')
 
 class Foo(Generic[T]):
     def f1(self: Foo[str]) -> None:
-        self.f2()  # E: Invalid self argument "Foo[str]" to attribute function "f2" with type "Callable[[Foo[int]], None]"
+        self.f2()  # E: Invalid self parameter "Foo[str]" to attribute function "f2" with type "Callable[[Foo[int]], None]"
     def f2(self: Foo[int]) -> None:
-        self.f1()  # E: Invalid self argument "Foo[int]" to attribute function "f1" with type "Callable[[Foo[str]], None]"
+        self.f1()  # E: Invalid self parameter "Foo[int]" to attribute function "f1" with type "Callable[[Foo[str]], None]"
 
 [case testSelfTypeStructureMetaclassMatch]
 from typing import TypeVar, Type, Generic, cast
@@ -1019,7 +1019,7 @@ class Bad(metaclass=Meta):
     pass
 
 Good.do_x()
-Bad.do_x()  # E: Invalid self argument "type[Bad]" to attribute function "do_x" with type "Callable[[type[T]], T]"
+Bad.do_x()  # E: Invalid self parameter "type[Bad]" to attribute function "do_x" with type "Callable[[type[T]], T]"
 
 [case testSelfTypeProtocolClassmethodMatch]
 from typing import Type, TypeVar, Protocol
diff --git a/test-data/unit/check-typevar-tuple.test b/test-data/unit/check-typevar-tuple.test
index 703653227e20..2823977be37f 100644
--- a/test-data/unit/check-typevar-tuple.test
+++ b/test-data/unit/check-typevar-tuple.test
@@ -2034,12 +2034,12 @@ class B(Generic[Unpack[Ts]]):
     def on_pair(self: B[T, S]) -> Tuple[T, S]: ...
 
 b1: B[int]
-reveal_type(b1.on_pair())  # E: Invalid self argument "B[int]" to attribute function "on_pair" with type "Callable[[B[T, S]], tuple[T, S]]" \
+reveal_type(b1.on_pair())  # E: Invalid self parameter "B[int]" to attribute function "on_pair" with type "Callable[[B[T, S]], tuple[T, S]]" \
                            # N: Revealed type is "tuple[Never, Never]"
 b2: B[int, str]
 reveal_type(b2.on_pair())  # N: Revealed type is "tuple[builtins.int, builtins.str]"
 b3: B[int, str, int]
-reveal_type(b3.on_pair())  # E: Invalid self argument "B[int, str, int]" to attribute function "on_pair" with type "Callable[[B[T, S]], tuple[T, S]]" \
+reveal_type(b3.on_pair())  # E: Invalid self parameter "B[int, str, int]" to attribute function "on_pair" with type "Callable[[B[T, S]], tuple[T, S]]" \
                            # N: Revealed type is "tuple[Never, Never]"
 
 class C(B[T, S]): ...