hologonidium [hol-oh-guh-nid-ee-uh m, hoh-loh-] Word Origin noun, plural hol·o·go·nid·i·a [hol-oh-guh-nid-ee-uh, hoh-loh-] /ˌhɒl oʊ gəˈnɪd i ə, ˌhoʊ loʊ-/. Botany, Mycology. soredium. Origin of hologonidium From New Latin; see origin at holo-, gonidium