Szemerényi's law

Etymology
Named after Hungarian linguist Oswald Szemerényi.

Proper noun

 * 1)  A sound change and a synchronic phonological rule that operated during an early stage of the Proto-Indo-European language. The rule deleted coda fricatives *s or laryngeals *h₁, *h₂ or *h₃ (cover symbol *H), with compensatory lengthening occurring in a word-final position.