acephalus

noun
aceph·​a·​lus | \ (ˈ)ā-ˈsef-ə-ləs, ə-ˈsef- How to pronounce acephalus (audio) \
plural acephali\ -​ˌlī, -​ˌlē How to pronounce acephali (audio) \

Medical Definition of acephalus

: a headless fetus