Definition of acron in US English:

acron

noun

Zoology
  • In an arthropod: the unsegmented region at the anterior end of the body; specifically the prostomial region of an arthropod embryo.

Origin

Early 20th century; earliest use found in Journal of the Royal Microscopical Society. From French acron from ancient Greek ἄκρον extremity, use as noun of neuter of ἄκρος highest, topmost.