ˈäˌbegz-, -eks- noun
Usage: capitalized A
Etymology: after Richard Abegg died 1910 German chemist
: a rule in chemistry: the sum of the hydrogen valence and the maximum oxygen valence of a chemical element is often equal to 8 [as of silicon in SiH 4 (-4) and SiO 2 (+4) or of sulfur in H 2 S (-2) and H 2 SO 4 (+6)]