Of or pertaining to the Oscines: applied to those Passeres which are acromyodian and to their type of structure: as, an oscine bird; an oscine syrinx. Also oscinine, oscinian.n. An oscine bird; a member of the Oscines.n. A crystalline alkaloid, C8H13O2N, found in crude belladonine and also made from other alkaloids. It melts at 110° C. Also called pseudatropine, scopoline, and oxytropine.