LSJ
τό, = σύμβολον, signal, Aen.Tact. 4.1, al. ; δεδώκει σ. Ev. Marc. 14.44; τὸ σ. ἀνέβη LXX Jd. 20.40; αἴρειν τὸ σ. Str. 6.3.3, D.S. 11.22; ἦρε τὸ συγκείμενον πρὸς μάχην σ. Id. 20.51.
stamp on weights and measures, ἀπὸ συσσήμου πωλεῖν Str. 15.1.51.
badge, ensign, τὰ τῆς ἀρχῆς σ.
insignia, regalia, D.S. 1.70; token, means of recognition, Men. Pk. 362 (censured by Phryn. 393); metaph of a patronymic, Ps.-Plu. Vit. Hom. 24.
pledge, pawn, Hedyl. ap. Ath. 8.345b.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)
TBESG
σύσ-σημον (T, συν-), -ου, τό
(< σῆμα), [in LXX: Jdg.20:38, 40 (מַשְׂאֵת), Isa.5:26 49:22 62:10 (נֵס) * ;]
a fixed sign or signal: Mrk.14:44. (Strab., Plut., al.; condemned by Atticists, see Rutherford, NPhr., 492 f.) †
(AS)
Translators Brief lexicon of Extended Strongs for Greek based on Abbot-Smith, A Manual Greek Lexicon of the New Testament (1922) (=AS), with corrections and adapted by Tyndale Scholars