Strong's 4594 (σήμερον)

this (to-)day

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

neuter (as adverb) of a presumed compound of the article G3588 (ὁ) (t changed to s) and G2250 (ἡμέρα);