napiform

adjective

na·​pi·​form ˈnā-pə-ˌfȯrm 

: globular at the top and tapering off abruptly

a napiform root

Word History

Etymology

borrowed from New Latin napiformis, from Latin nāpus "turnip" + -ifōrmis -iform — more at neep

First Known Use

circa 1841, in the meaning defined above