diff --git a/src/geometry/isometry.rs b/src/geometry/isometry.rs
index 3eebb93a..435585f7 100644
--- a/src/geometry/isometry.rs
+++ b/src/geometry/isometry.rs
@@ -20,7 +20,7 @@ use base::storage::Owned;
 use base::{DefaultAllocator, MatrixN};
 use geometry::{Point, Translation};
 
-/// A direct isometry, i.e., a rotation followed by a translation.
+/// A direct isometry, i.e., a rotation followed by a translation, aka. a rigid-body motion, aka. an element of a Special Euclidean (SE) group.
 #[repr(C)]
 #[derive(Debug)]
 #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
diff --git a/src/geometry/isometry_alias.rs b/src/geometry/isometry_alias.rs
index fba07e5e..a0804b5c 100644
--- a/src/geometry/isometry_alias.rs
+++ b/src/geometry/isometry_alias.rs
@@ -2,14 +2,14 @@ use base::dimension::{U2, U3};
 
 use geometry::{Isometry, Rotation2, Rotation3, UnitComplex, UnitQuaternion};
 
-/// A 2-dimensional direct isometry using a unit complex number for its rotational part.
+/// A 2-dimensional direct isometry using a unit complex number for its rotational part. Also known as a rigid-body motion, or as an element of SE(2).
 pub type Isometry2<N> = Isometry<N, U2, UnitComplex<N>>;
 
-/// A 3-dimensional direct isometry using a unit quaternion for its rotational part.
+/// A 3-dimensional direct isometry using a unit quaternion for its rotational part. Also known as a rigid-body motion, or as an element of SE(3).
 pub type Isometry3<N> = Isometry<N, U3, UnitQuaternion<N>>;
 
-/// A 2-dimensional direct isometry using a rotation matrix for its rotational part.
+/// A 2-dimensional direct isometry using a rotation matrix for its rotational part. Also known as a rigid-body motion, or as an element of SE(2).
 pub type IsometryMatrix2<N> = Isometry<N, U2, Rotation2<N>>;
 
-/// A 3-dimensional direct isometry using a rotation matrix for its rotational part.
+/// A 3-dimensional direct isometry using a rotation matrix for its rotational part. Also known as a rigid-body motion, or as an element of SE(3).
 pub type IsometryMatrix3<N> = Isometry<N, U3, Rotation3<N>>;