sign (n.) Look up sign at Dictionary.com
early 13c., "gesture or motion of the hand," from O.Fr. signe "sign, mark, signature," from L. signum "mark, token, indication, symbol," from PIE base *sekw- "point out" (see see). Meaning "a mark or device having some special importance" is recorded from late 13c.; that of "a miracle" is from c.1300. Sense of "characteristic device attached to the front of an inn, shop, etc., to distinguish it from others" is first recorded mid-15c. Ousted native token. In some uses, the word probably is aphetic for ensign. First record of signage is from 1976. Sign language is recorded from 1847.
sign (v.) Look up sign at Dictionary.com
c.1300, "to make the sign of the cross," from O.Fr. signer, from L. signare, from signum (see sign (n.)). Sense of "to mark, stamp" is attested from mid-14c.; that of "to affix one's name" is from late 15c. Meaning "to communicate by sign language" is recorded from 1700.