ˈnafˌthil, ÷ˈnapˌ- noun
( -s )
Etymology: International Scientific Vocabulary naphth- + -yl
: either of two univalent hydrocarbon radicals C 10 H 7 derived from naphthalene:
a. : the radical derived by removal of a hydrogen atom in the alpha or 1-position — called also alpha-naphthyl, 1-naphthyl
b. : the radical derived by removal of a hydrogen atom in the beta or 2-position — called also beta-naphthyl, 2-naphthyl