Lexical Definition

‎σήμερον‎ sḗmeron (say'-mer-on) today ^G:ADV
neuter (as adverb) of a presumed compound of the article ‎ὁ‎ (t changed to s) and ‎ἡμέρα‎

this (to-)day.

• on the (i.e. this) day (or night current or just passed)
• generally, now (i.e. at present, hitherto)

Abbott-Smith

σήμερον (Att.. τήμερον), adv., [in LXX for הַיּוֺם ;]
to-day: Mt 6:11, Lk 4:21, Ac 4:9, al.; opp. to αὔριον, Mt 6:30, Lk 12:28, Ja 4:13; χθὲς καὶ σ. καὶ εἰς τοὺς αἰῶνας, He 13:8; ἡ σ. ἡμέρα, Ac 20:26; ἕως (ἄχρι) τῆς σ. ἡμέρας, Ro 11:8, II Co 3:14; μέχρι (ἕως) τῆς σ. (sc. ἡμέρας), Mt 11:23 27:8; as subst., τὸ σ., He 3:13; id. in appos., ὁρίζει ἡμέραν, σ., He 4:7 R, mg., (v. Westc., in l.).

Abbott-Smith References

Liddell-Scott-Jones

σήμερον,

adverb to-day, [NT+8th c.BC+]; Doric dialect σάμερον [ᾱ] [Refs 5th c.BC+]; Attic dialect τήμερον [σήμερον">Refs 5th c.BC+] is sometimes found in Comedy texts, [Refs 5th c.BC+]; εἰς τ. [Refs 5th c.BC+]; τὸ τ. εἶναι to-day, [Refs 4th c.BC+]; also in the form τήμερα [Refs 5th c.BC+]. (Prob. from κyᾱμερον, containing stem [kcirc]yo- 'this', cf. Lithuanian šis 'this', Latin ci-tra: σήμερον (τήμερον) is to ἡμέρα as σῆτες (τῆτες) to ἔτος.)

_{LSJ Scripture Refs: Matt.27.19}