diff --git a/boltons/strutils.py b/boltons/strutils.py
index bbc9d73..b8c25fb 100644
--- a/boltons/strutils.py
+++ b/boltons/strutils.py
@@ -241,7 +241,7 @@ _IRR_S2P = {'alumnus': 'alumni', 'analysis': 'analyses', 'antenna': 'antennae',
             'diagnosis': 'diagnoses', 'ellipsis': 'ellipses', 'fish': 'fish',
             'focus': 'foci', 'foot': 'feet', 'formula': 'formulae',
             'fungus': 'fungi', 'genus': 'genera', 'goose': 'geese',
-            'hypothesis': 'hypotheses', 'index': 'indeces', 'louse': 'lice',
+            'hypothesis': 'hypotheses', 'index': 'indices', 'louse': 'lice',
             'man': 'men', 'matrix': 'matrices', 'means': 'means',
             'medium': 'media', 'memorandum': 'memoranda', 'mouse': 'mice',
             'nebula': 'nebulae', 'nucleus': 'nuclei', 'oasis': 'oases',