Cowgill's law (Greek)

In Ancient Greek, Cowgill's law says that a former /o/ vowel becomes /u/ between a resonant (/r/, /l/, /m/, /n/) and a labial consonant (including labiovelars), in either order. It is named after the American Indo-Europeanist Warren Cowgill.

This article contains characters used to write reconstructed Proto-Indo-European words (for an explanation of the notation, see Proto-Indo-European phonology). Without proper rendering support, you may see question marks, boxes, or other symbols instead of Unicode combining characters and Latin characters.

Examples:

• Ancient Greek: νύξ 'night' < PIE *nokʷts (cf. Latin: nox, Vedic nák < *nakts, Gothic: nahts, gen. sg. Hittite: nekuz)
• Ancient Greek: φύλλον 'leaf' < PIE *bʰolyom (cf. Latin: folium)
• Ancient Greek: μύλη 'mill' < PIE *mol-eh₂- (cf. Latin: molīna)
• Ancient Greek: ὄνυξ 'nail' (stem Proto-Greek: *ónukh-) < early PG *onokʷʰ- < PIE *h₃nogʷʰ- (cf. Old English: nægl < PGerm *nag-laz)

Note that when a labiovelar adjoins an /o/ affected by Cowgill's law, the new /u/ will cause the labiovelar to lose its labial component (as in Greek: núks and Greek: ónuks/ónukh-, where the usual Greek change *kʷ > *p has not occurred).

Counterexamples:

Attic Greek: ὄνομα 'name' alongside expected Doric and Aeolic ὄνυμα.^[1]