diff --git a/readme.md b/readme.md
index 1001a59..1c971d4 100644
--- a/readme.md
+++ b/readme.md
@@ -4112,7 +4112,7 @@ Square with one rounded corner.
 ---
 <a name="Round"></a>
 ## Round
-Round 2D shapes uisng `offset()`, which is fast and 3D shapes with [`offset_3D()`](#offset), which is very slow.
+Round 2D shapes using `offset()`, which is fast and 3D shapes with [`offset_3D()`](#offset), which is very slow.
 
 A single radius can be specified or separate internal and external radii.
 If `chamfer_base` is `true` for `round_3D()` then the bottom edge is made suitable for 3D printing by chamfering once the
diff --git a/utils/round.scad b/utils/round.scad
index bab60aa..a4c0b73 100644
--- a/utils/round.scad
+++ b/utils/round.scad
@@ -17,7 +17,7 @@
 // If not, see <https://www.gnu.org/licenses/>.
 //
 
-//! Round 2D shapes uisng `offset()`, which is fast and 3D shapes with [`offset_3D()`](#offset), which is very slow.
+//! Round 2D shapes using `offset()`, which is fast and 3D shapes with [`offset_3D()`](#offset), which is very slow.
 //!
 //! A single radius can be specified or separate internal and external radii.
 //! If `chamfer_base` is `true` for `round_3D()` then the bottom edge is made suitable for 3D printing by chamfering once the