Centum

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.