diff --git a/python/geometric_structure/cusp_neighborhood/cusp_cross_section.py b/python/geometric_structure/cusp_neighborhood/cusp_cross_section.py
index ace9073a..effa9123 100644
--- a/python/geometric_structure/cusp_neighborhood/cusp_cross_section.py
+++ b/python/geometric_structure/cusp_neighborhood/cusp_cross_section.py
@@ -1193,7 +1193,7 @@ def move_fixed_point_to_zero(self):
         corresponding cusp triangles so that the fixed point is at the
         origin.
 
-        It also add the boolean v.is_complete to all vertices of the
+        It also adds the boolean v.is_complete to all vertices of the
         triangulation to mark whether the corresponding cusp is
         complete or not.
         """