I. noun 1.
[Anatomy] a natural protuberance from a bone, or inside the shell or exoskeleton of a sea urchin or insect, for the attachment of muscles.
[Botany] a swelling at the base of the sporangium in some mosses.
[Geology] a small offshoot extending from an igneous intrusion into the surrounding rock.
II. derivatives apophyseal /ˌapəˈfɪsɪəl / adjective
– origin late 16th cent.: modern Latin, from Greek apophusis ‘offshoot’, from apo- ‘from, away’ + phusis ‘growth’.