Emily Dickinson Lexicon

AR'IL, or AR-IL'LUS, n.

The exterior coat or covering of a seed, fixed to it at the base only, investing it wholly or partially, and falling off spontaneously; by some writers called, from the Greek, Calyptra. It is either succulent, or cartilaginous; colored, elastic, rough or knotted. – Linnæus. Milne. Martyn. Smith. An expansion of the placenta about a seed, into a fleshy body, as the mace of a nutmeg. Lindley.