Centum is the collective name for the branches of Indo-European (see:
Indo-European languages) in which the so-called Satem shift (the change of palato-velar *k
^, *g
^, *g
^h into fricatives or affricates; see:
affricate) did not take place, and the palato-velar consonants merged with plain velars (*k, *g, *g
h). Most of the Centum languages preserve Proto-Indo-European labio-velars (*k
w, *g
w, *g
wh) or their historical reflexes as distinct from plain
velars; for example, PIE *k, *k
w > Latin
c /k[?]/,
qu /k[?]w/, Greek
/k[?]/,
/p[?]/ (or
/t[?]/ before front vowels), Gothic
/h[?]/,
/h[?]w/, etc.
The name Centum comes from the Latin word centum '100', pronounced [kentum] < PIE *k^mtom, illustrating the falling together of *k and *k^. Compare Sanskrit s′ata- or Russian sto, in which *k^ changed into a fricative (see: Satem).
The Centum branches (which, by the way, developed independently from Proto-Indo-European and do not constitute a valid genetic unit) include Anatolian, Tocharian, Italic, Celtic, Germanic, Greek, and probably a number of minor and little known extinct groups.