G4594 σήμερον (sḗmeron)

KJV renderings: this (to-)day
Strong's definition: on the (i.e. this) day (or night current or just passed); generally, now (i.e. at present, hitherto)
Derivation: neuter (as adverb) of a presumed compound of the article G3588 (ὁ) (t changed to s) and G2250 (ἡμέρα);

From James Strong's public-domain dictionaries (G), JSON edition by OpenScriptures (CC-BY-SA). Every dotted-underline word in the text links here.