Entry 1 sense Webster, 1913 Endomorph · En·do·morph · IPA /ˈɛndoʊmɔːɹf/ 01 n. A crystal of one species inclosed within one of another, as one of rutile inclosed in quartz. 1. A crystal of one species inclosed within one of another, as one of rutile inclosed in quartz.(Min.)