What is "epicoele"

Epicoele \Ep"i*coele\ ([e^]p"[i^]*s[=e]l), n. [Pref. epi- + Gr. koi^lon a hollow.] (Anat.) A cavity formed by the invagination of the outer wall of the body, as the atrium of an amphioxus and possibly the body cavity of vertebrates.

n. (context anatomy English) A cavity formed by the invagination of the outer wall of the body, as the atrium of an amphioxus and possibly the body cavity of vertebrates.