An Etymological Dictionary of Astronomy and Astrophysics

1. Physics, Chem.: A distinctive trace or sign that indicates the presence of a substance or the occurrence of a physical process or event.
   

2. Telecommunication: The complete set of electromagnetic and/or acoustic signals received, e.g., from an infrared source, a radio or radar transmitter, an aircraft, or a ship. Signatures may consist of analog or digital signals, or both, and may be analyzed to indicate the nature of their source and assist in its recognition.

Etymology (EN): M.Fr. signature, from M.L. signatura “sign,” in classical L. “the matrix of a seal,” from signatus, p.p. of signare “to mark, sign,” → sign.

Etymology (PE): Nešânzad, literally “striking a mark, sign” (cf. angošt zadan “fingerprint”), from nešân, → sign, + zad past stem of zadan “to strike, beat; to do; to play an instrument” (Mid.Pers. zatan, žatan; O.Pers./Av. jan-, gan- “to strike, hit, smite, kill” (jantar- “smiter”); cf. Skt. han- “to strike, beat” (hantar- “smiter, killer”); Gk. theinein “to strike;” L. fendere “to strike, push;” Gmc. *gundjo “war, battle;” PIE *g^when- “to strike, kill”).