epactal,a.Anat.|ɪˈpæktəl, ɛˈpæktəl| [f.Gr. ἐπακτός (seeprec.) + -al1.] ‘Imported; foreign’ (Syd. Soc.Lex.). epactal bone: the Wormian bone at the superior angle of the occipital bone. 1878Bartley tr.Topinard's Anthrop. ii. i. 207 The exceptionally large ossa Wormiana..an epactal, for example.