卵らん割かつ腔こうらんかつこうMeanings1nouncleavage cavity; segmentation cavityEmbryological term for the fluid-filled space inside a blastula; also called 割腔 (かっこう).See also: 割腔卵らん割かつ腔こうは胞ほう胚はいの内ない部ぶに形けい成せいされる。The cleavage cavity forms inside the blastula.