signee n.

early 13c., signen, "to make the sign of the cross," from Old English segnian and Old French signier "to make a sign (to someone); to mark," both of them from Latin signare "to set a mark upon, mark out, designate; mark with a stamp; distinguish, adorn;" figuratively "to point out, signify, indicate," from signum "identifying mark, sign" (see sign (n.)).

The sense of "to mark, stamp" is attested from mid-14c.; that of "affix one's name or signature to" is from late 15c. The meaning "communicate by hand signs, make known by significant motion" is recorded from 1700.

Transitive sense in baseball, "engage (a player) by the signing of an agreement" is by 1889. To sign out (transitive) "secure the release of (someone or something) by signing" is attested by 1963, of library books. The intransitive sense of "record one's departure" is recorded by 1951. Related: Signed; signing.

word-forming element in legal English (and in imitation of it), representing the Anglo-French -é ending of past participles used as nouns (compare -y (3)). As these sometimes were coupled with agent nouns in -or, the two suffixes came to be used as a pair to denote the initiator and the recipient of an action.

Not to be confused with the French -ée that is a feminine noun ending (as in fiancée), which is from Latin -ata.