Webster’s Revised Unabridged Dictionary · 1913
Chorion
Cho′ri·on, n. [NL., fr. Gr. χορίον.]
1. (Anat.) (a) The outer membrane which invests the fetus in the womb; also, the similar membrane investing many ova at certain stages of development. (b) The true skin, or cutis.
2. (Bot.) The outer membrane of seeds of plants.