LSJ
τό, remembrance, memorial of a thing, μνημόσυνον ἑωυτοῦ λιπέσθαι Hdt. 1.185, 4.166; μνημόσυνον λιπέσθαι Id. 1.186, 2.101; μνημόσυνα ἀποδέξασθαι ib. 148, al. ; rare in early Att. Prose, Th. 5.11; μ. στοργῆς AP 12.68 (Mel.); εἰς μ. τινός Ev. Matt. 26.13, cf. Act. Ap. 10.4.
memorandum, reminder, μνημόσυνα γράψομαι Ar. V. 538; τουτὶ… ἔστω τὸ μ. μοι ib. 559.
mark, scar, μ. ὑποκαταλιπεῖν Hp. Prorrh. 2.20.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)
TBESG
μνημόσυνον, -ου, τό
(< μνήμων, mindful), [in LXX freq. for זֵכֶר, זִכְרוֹן and cogn. forms ;]
a memorial: Mat.26:13, Mrk.14:9, Act.10:4 (where cf. Lev.2:9, 16 5:12, Num_5:28, Sir.45:16, al.).†
(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