a. Half radial. [ Webster 1913 Suppl. ]
. (Mach.) See Radial engine, above. [ Webster 1913 Suppl. ]
a. (Zool.) Half hidden or half covered; said of the head of an insect when half covered by the shield of the thorax. [ 1913 Webster ]
n. (Anat.) One of the incomplete rings of the upper part of the bronchial tubes of most birds. The semirings form an essential part of the syrinx, or musical organ, of singing birds. [ 1913 Webster ]