Entry 1 sense Webster, 1913 Gyrencephala /(jĭr`ĕn*sĕf"ȧ*lȧ)/ · Gyr·en·ceph·a·la · IPA 01 n. pl. The higher orders of Mammalia, in which the cerebrum is convoluted. 1. The higher orders of Mammalia, in which the cerebrum is convoluted.(Zool.)