H0354900 (hĭp′ə-bĭs′əl, hī′pə-)adj.Geology Solidifying chiefly as a minor intrusion, especially as a dike or sill, before reaching the earth's surface. Used of rocks.hyp′a·bys′sal·ly adv.
hypabyssally
(ˌhɪpəˈbɪsəlɪ) adv (Geological Science) in a hypabyssal manner