diff --git a/aiidalab_widgets_base/structures.py b/aiidalab_widgets_base/structures.py
index 3a3cbf92..1433f314 100644
--- a/aiidalab_widgets_base/structures.py
+++ b/aiidalab_widgets_base/structures.py
@@ -976,7 +976,7 @@ def __init__(self, title="Cell transform"):
                 ipw.VBox(
                     [
                         ipw.HTML(
-                            "<b>Cell Transformation:</b>",
+                            "<b>Cell transformation:</b>",
                             layout={"margin": "20px 0px 10px 0px"},
                         ),
                         self.cell_transformation,