hydrencephal, -ic, -oid, -on, -us [f. hydro- b + Gr. ἐγκέϕαλος brain]: see hydrocephale, etc. 1847Craig, Hydrencephalic..Hydrencephalus.1866–80A. Flint Princ.Med. (ed. 5) 704 The so-called hydrencephaloid affection incident, in children, to exhaustion from diarrhoea.