Entry 1 sense Webster, 1913 Naphthide /(năf"thĭd [or] năf"thīd)/ · Naph·thide · IPA 01 n. A compound of naphthalene or its radical with a metallic element; as, mercuric naphthide. 1. A compound of naphthalene or its radical with a metallic element; as, mercuric naphthide.(Chem.)