epiplastron

Coined by Thomas Henry Huxley in 1872 as epi- +‎ plastron. Superseded the earlier episternum, a nominalised form of the French adjective épisternal, coined by Étienne Geoffroy Saint-Hilaire in 1818. The prefix is from Ancient Greek ἐπί (epí, “on top of”), in reference to its position as the anteriormost bone of the plastron.