| ̷ ̷ ̷ ̷ˌ ̷ ̷+ noun
Etymology: International Scientific Vocabulary phenylene + diamine
: any of three toxic isomeric crystalline compounds C 6 H 4 (NH 2 ) 2 that are ortho, meta, and para diamino derivatives of benzene of which the ortho and para isomers are used as photographic developers and the meta and para isomers in dye manufacture