Meaning
an adjective, signifying "known" (from ginosko, "to know"), is used (a) as an adjective, most usually translated "known," whether of facts, e.g., Act 1:19, Act 2:14, Act 4:10; or persons, Joh 1:18-16; it denotes "notable" in Act 4:16, of a miracle; (b) as a noun, "acquaintance," Luk 2:44, Luk 23:49. See ACQUAINTANCE, KNOWN.
<2,,1978, episemos>
primarily meant "bearing a mark," e.g., of money, "stamped, coined," (from epi, "upon," and sema, "a mark, a sign;" cp. semaino, "to give a sign, signify, indicate," and semeioo, "to note;" see below); it is used in the NT, metaphorically, (a) in a good sense, Rom 16:7, "of note, illustrious," said of Andronicus and Junias; (b) in a bad sense, Mat 27:16, "notable," of the prisoner Barabbas. In the Sept., Gen 30:42, Est 5:4, Est 8:13, toward the end of the verse, "a distinct (day)".
<3,,2016, epiphanes>
"illustrious, renowned, notable" (akin to epiphaino, "to show forth, appear;" Eng., "epiphany"), is translated "notable" in Act 2:20, of the great Day of the Lord. The appropriateness of this word (compared with Nos. 1 and 2) to that future occasion is obvious.