Ar"il (#), A*ril"lus (#), n. [From LL. arilli dry grapes, perh. fr. L. aridus dry: cf. F,. arille.] Bot.
A exterior covering, forming a false coat or appendage to a seed, as the loose, transparent bag inclosing the seed or the white water lily. The mace of the nutmeg is also an aril.
© Webster 1913.