xiphiplastron

Century Dictionary and Cyclopedia

1. n. The fourth lateral piece of the plastron of a turtle; one of the pair of terminal pieces of the plastron in Chelonia, called xiphisternum by some. See cuts under plastron and Chelonia.

Wiktionary

1. n. the posterior, or fourth lateral plate in the plastron of a turtle

GNU Webster's 1913

1. n. The posterior, or fourth, lateral plate in the plastron of turtles; -- called also xiphisternum.