īˈsästəˌrizəm; ˈ ̷ ̷ ̷ ̷ at iso- +ˌstiˌrizəm or ˌsteˌr- noun
( -s )
Etymology: is- + ster- (from Greek stereos solid) + -ism
: the phenomenon of similarity of structure and of resulting similarity of some properties exhibited by two or more molecules or groups or ions containing different atoms though not necessarily the same number of atoms but having the same number of total or valence electrons in the same arrangement (as in carbon monoxide and gaseous nitrogen or in the cyanide and acetylide ions)