The Collaborative International Dictionary
Nectosac
Nectosac \Nec"to*sac\, Nectosack \Nec"to*sack\, n. [Gr. nhkto`s swimming + E. sac, sack.] (Zo["o]l.) The cavity of a nectocalyx.
Wiktionary
nectosac
n. (context zoology rare chiefly in the plural English) The cavity of a nectocalyx.