An Etymological Dictionary of Astronomy and Astrophysics

The reason for which something exists or is done, made, used, etc. (Dictionary.com).

Etymology (EN): M.E. purpos, from O.Fr. porpos “aim, intention,” from porposer “to put forth,” from por- “forth,” from L. → pro- “forth;” + O.Fr. poser “to put, place,” → position.

Etymology (PE): Farneh, literally “put forth,” from far-, variant of farâ-, → pro-,

• neh present stem of nehâdan “to pose, place, lay,” → position.