diff --git a/usr.bin/units/units.lib b/usr.bin/units/units.lib
index c5a002137e7..1c2a1fa814b 100644
--- a/usr.bin/units/units.lib
+++ b/usr.bin/units/units.lib
@@ -455,7 +455,7 @@ mgd			megagal/day
 mh			millihenry
 mhz			1e+6 /sec
 mil			1e-3 in
-millenium		1000 year
+millennium		1000 year
 minersinch		1.5 ft3/min
 minim			1|60 fldr
 mo			month