diff --git a/codespell_lib/data/dictionary.txt b/codespell_lib/data/dictionary.txt
index 50bf56e..309d979 100644
--- a/codespell_lib/data/dictionary.txt
+++ b/codespell_lib/data/dictionary.txt
@@ -3,6 +3,7 @@
 2st->2nd
 3nd->3rd
 3st->3rd
+4rd->4th
 a-diaerers->a-diaereses
 aaccessibility->accessibility
 aaccession->accession