diff --git a/check_source/check_spelling_c_config.py b/check_source/check_spelling_c_config.py
index 88580e0a23f6d48de6876ba217ecfd0d739b0fd5..51733146100aa8179be21a7eb5ca45c406440fd7 100644
--- a/check_source/check_spelling_c_config.py
+++ b/check_source/check_spelling_c_config.py
@@ -76,6 +76,7 @@ dict_custom = {
     "decorrelated",
     "decrement",
     "decrementing",
+    "deduplicate",
     "deduplicating",
     "deduplication",
     "defocus",