diff --git a/ndrect/_is_aligned.py b/ndrect/_ndrect_base.py
similarity index 94%
rename from ndrect/_is_aligned.py
rename to ndrect/_ndrect_base.py
index 0212027..fb47a6c 100644
--- a/ndrect/_is_aligned.py
+++ b/ndrect/_ndrect_base.py
@@ -1,4 +1,4 @@
-"""IsAligned interface for N-dimensional rectangles with defined shapes."""
+"""Base class for N-dimensional rectangles."""
 
 from __future__ import annotations
 
@@ -14,8 +14,8 @@
     from ndrect.ndrect_complex import NDRectComplex
 
 
-class IsAligned[TSingular: NDRect, TComplex: NDRectComplex](ABC):
-    """An interface for N-dimensional rectangles that have a defined shape."""
+class NDRectBase[TSingular: NDRect, TComplex: NDRectComplex](ABC):
+    """Base class for N-dimensional rectangles."""
 
     @property
     @abstractmethod
@@ -83,7 +83,7 @@ def _as_sequence_object(
             return tuple(self.rects)
         raise TypeError
 
-    def then(self, other: IsAligned) -> TComplex:
+    def then(self, other: NDRectBase) -> TComplex:
         """Sequences the other rectangle after this one.
 
         Args:
@@ -161,7 +161,7 @@ def __mul__(self, n: int) -> TComplex:
         """
         return self.repeat(n)
 
-    def __add__(self, other: IsAligned) -> TComplex:
+    def __add__(self, other: NDRectBase) -> TComplex:
         """Shorthand for :meth:`then`.
 
         Sequences the other rectangle after this one.
diff --git a/ndrect/ndrect.py b/ndrect/ndrect.py
index 1648170..018bf21 100644
--- a/ndrect/ndrect.py
+++ b/ndrect/ndrect.py
@@ -9,7 +9,7 @@
 
 from attrs import define, field
 
-from ndrect._is_aligned import IsAligned
+from ndrect._ndrect_base import NDRectBase
 from ndrect._typing import DimensionLength, DimensionName
 
 if TYPE_CHECKING:
@@ -17,7 +17,7 @@
 
 
 @define(repr=False)
-class NDRect(IsAligned["NDRect", "NDRectComplex"]):
+class NDRect(NDRectBase["NDRect", "NDRectComplex"]):
     """An n-dim rectangle defined by its shape."""
 
     shape: Mapping[DimensionName, DimensionLength] = field(
diff --git a/ndrect/ndrect_complex.py b/ndrect/ndrect_complex.py
index 0fae93f..097c53d 100644
--- a/ndrect/ndrect_complex.py
+++ b/ndrect/ndrect_complex.py
@@ -8,7 +8,7 @@
 
 from attrs import define, field
 
-from ndrect._is_aligned import IsAligned
+from ndrect._ndrect_base import NDRectBase
 from ndrect._typing import DimensionLength, DimensionName
 
 if TYPE_CHECKING:
@@ -28,7 +28,7 @@ class UnalignedError(Exception):
 
 
 @define(repr=False, frozen=True)
-class NDRectComplex(IsAligned["NDRect", "NDRectComplex"]):
+class NDRectComplex(NDRectBase["NDRect", "NDRectComplex"]):
     """Aligned complex n-dim rectangle of multiple rectangles in sequence."""
 
     rects: Sequence[NDRect | NDRectComplex] = field(converter=tuple)
diff --git a/tests/ndrect/test__is_aligned.py b/tests/ndrect/test__ndrect_base.py
similarity index 88%
rename from tests/ndrect/test__is_aligned.py
rename to tests/ndrect/test__ndrect_base.py
index fd32507..37bf86f 100644
--- a/tests/ndrect/test__is_aligned.py
+++ b/tests/ndrect/test__ndrect_base.py
@@ -8,12 +8,12 @@
 from attrs import define
 
 from ndrect import NDRect
-from ndrect._is_aligned import IsAligned
+from ndrect._ndrect_base import NDRectBase
 from ndrect._typing import DimensionLength, DimensionName
 from ndrect.ndrect_complex import NDRectComplex
 
 
-class MockIsAligned(IsAligned):
+class MockNDRectBase(NDRectBase):
     @property
     def shape(self) -> MappingProxyType[DimensionName, DimensionLength]:
         return ...
@@ -49,9 +49,9 @@ def _complex_type(self) -> type[MockNDRectComplex]:
         return MockNDRectComplex
 
 
-@patch.object(MockIsAligned, "shape", new_callable=PropertyMock)
+@patch.object(MockNDRectBase, "shape", new_callable=PropertyMock)
 def test_ndim_is_len_of_shape(mock_shape: PropertyMock) -> None:
-    obj = MockIsAligned()
+    obj = MockNDRectBase()
     ndim = obj.ndim
     mock_shape.assert_called_once()
     assert ndim == len(obj.shape)
@@ -131,31 +131,31 @@ def test_along_creates_complex_with_align_dim_using_as_sequence_object(
 
 
 def test___add__calls_then() -> None:
-    with patch.object(MockIsAligned, "then") as mock_then:
-        obj_a = MockIsAligned()
-        obj_b = MockIsAligned()
+    with patch.object(MockNDRectBase, "then") as mock_then:
+        obj_a = MockNDRectBase()
+        obj_b = MockNDRectBase()
         assert obj_a + obj_b == mock_then.return_value
         mock_then.assert_called_once_with(obj_b)
 
 
 def test___mul__calls_repeat() -> None:
-    with patch.object(MockIsAligned, "repeat") as mock_repeat:
-        obj = MockIsAligned()
+    with patch.object(MockNDRectBase, "repeat") as mock_repeat:
+        obj = MockNDRectBase()
         n = MagicMock()
         assert obj * n == mock_repeat.return_value
         mock_repeat.assert_called_once_with(n)
 
 
 def test__pos__calls_elevate() -> None:
-    with patch.object(MockIsAligned, "elevate") as mock_elevate:
-        obj = MockIsAligned()
+    with patch.object(MockNDRectBase, "elevate") as mock_elevate:
+        obj = MockNDRectBase()
         assert +obj == mock_elevate.return_value
         mock_elevate.assert_called_once()
 
 
 def test__matmul__calls_along() -> None:
-    with patch.object(MockIsAligned, "along") as mock_along:
-        obj = MockIsAligned()
+    with patch.object(MockNDRectBase, "along") as mock_along:
+        obj = MockNDRectBase()
         dim = MagicMock()
         assert obj @ dim == mock_along.return_value
         mock_along.assert_called_once_with(align_dim=dim)