/ab'ap tis"teuhn/ , n.
Surg. a cone-shaped trephine designed to avoid penetration of the brain when incising the skull.
[ 1690-1700; trýpanon ) abáptiston (trepan) not dipped, neut. of abáptistos, equiv. to a- A- 6 + baptis-, var. s. of baptízein to immerse (see BAPTIZE) + -tos verbal adj. suffix ]