The Collaborative International Dictionary
Acrotarsium
Acrotarsium \Ac`ro*tar"si*um\, n. [NL., from Gr. ? topmost + ? tarsus.] (Zo["o]l.) The instep or front of the tarsus.
Wiktionary
acrotarsium
n. (context zoology English) The instep or front of the tarsus.