The Latin word for hundred. It was pronounced with a hard K sound in Classical Latin, kentu(m).

In linguistics, the Indo-European languages have traditionally been divided into centum and satem groups, depending on whether the word for "hundred" kept its K sound, or changed it to an S sound. The word satem is Avestan for one hundred, and Avestan is a member of the Indo-Iranian branch. The ancestor of them all, Proto-Indo-European, is believed to have used the word kmtóm.

The word centum was perhaps an unfortunate choice, because of course in later Latin it changed to a CH sound then to S in French, Spanish, in Portuguese, blurring the distinction with satem.

The centum groups are

  • Italic e.g. Latin
  • Greek: hekaton containing a prefix he- from earlier sm- 'one'
  • Celtic e.g. Welsh cant, Irish cead
  • Germanic including English, German and the Scandinavian languages: these underwent further sound changes from kmt- to khunth- to hund-, and most have added the -red element, meaning 'a count', related to Latin ratio
  • Tocharian, the two extinct languages discovered in inscriptions in Xinjiang in China: their discovery scuppered the simple theory that you had centum languages in the west and satem ones in the east.
The satem groups are These days it's no longer believed that the Proto-Indo-European ancestor split into two branches first, along centum/satem lines. Rather, the change K > S spread across dialect boundaries over time: the dialects that would later become the major branches.