σημεῖον, σημείου, τό (σημαίνω (or σῆμα)), from Aeschylus and Herodotus down, Hebrew אות, a sign, mark, token;
1. universally, that by which a person or a thing is distinguished from others and known: Matthew 26:48; Luke 2:12; 2 Thessalonians 3:17; σημεῖον περιτομῆς (explanatory genitive (cf. Buttmann, § 123, 4)), equivalent to σημεῖον, ὁ ἐστι περιτομή, circumcision which should be a sign of the covenant formed with God, Romans 4:11; τά σημεῖα τοῦ ἀποστόλου, the tokens by which one is proved to be an apostle, 2 Corinthians 12:12; a sign by which anything future is pre-announced, Mark 13:4; Luke 21:7; τό σημεῖον τῆς σής παρουσίας, genitive of the object, Matthew 24:3; τοῦ υἱοῦ τοῦ ἀνθρώπου, the sign which indicates that the Messiah will shortly, or forthwith, come from heaven in visible manifestation, Matthew 24:30; with a genitive of the subjunctive τά σημεῖα τῶν καιρῶν, i. e. the indications of future events which οἱ καιροί furnish, what οἱ καιροί portend, Matthew 16:3 (T brackets WH reject the passage); a sign by which one is warned, an admonition, 1 Corinthians 14:22. used of noteworthy personages, by whom God forcibly admonishes men and indicates to them what he would have them do: thus σημεῖον ἀντιλεγόμενον is said of Jesus Christ, Luke 2:34; Ἰωνᾶς ἐγένετο σημεῖον τοῖς Νινευίταις (Jonah 3:4), Luke 11:30; hence, τό σημεῖον Ἰωνᾶ, Luke 11:29, is equivalent to τό σημεῖον like to that ὅς ἦν Ἰωνᾶς, i. e. to the sign which was given by the mission and preaching of Jonah, to prompt men to seek salvation (Winer's Grammar, 189 (177)); in the same sense, ὁ υἱός τοῦ ἀνθρώπου says that he will be a σημεῖον, to the men of his generation, Luke 11:30; but in Matthew 12:39; Matthew 16:4 τό σημεῖον Ἰωνᾶ is the miraculous experience which befell Jonah himself, cf. Matthew 12:40; that Luke reproduces Christ's words more correctly than Matthew is shown by De Wette and Bleek on Matthew 12:40, by Neander, Leben Jesu, p. 265f edition 1 (English translation, (3rd edition N. Y. 1851) § 165, p. 245f), and others; (but that Luke's report is less full than Matthew's, rather than at variance with it, is shown by Meyer, Weiss, Keil, and others (on Matthew, the passage cited)).
2. a sign, prodigy, portent, i. e. an unusual occurrence, transcending the common course of nature;
a. of signs portending remarkable events soon to happen: Luke 21:11, 25; Acts 2:19; Revelation 12:1, 3; Revelation 15:1.
b. of miracles and wonders by which God authenticates the men sent by him, or by which men prove that the cause they are pleading is God's: Matthew 12:38; Matthew 16:1, 4; Mark 8:11; Mark 16:17, 20; Luke 11:16, 29; Luke 23:8; John 2:11, 18, 23; John 3:2; John 4:54; John 6:2, 14, 26, 30; John 7:31; John 9:16; John 10:41; John 11:47; John 12:18, 37; John 20:30; Acts 2:22, 43; Acts 8:6; 1 Corinthians 1:22; but time power διδόναι σημεῖα, by which men are deceived, is ascribed also to false teachers, false prophets, and to demons: Matthew 24:24; Mark 13:22; Revelation 13:13; Revelation 16:14; Revelation 19:20; 2 Thessalonians 2:9. σημεῖα καί τέρατα (וּמֹפְתִים אֹתות) or (yet less frequent) τέρατα καί σημεῖα (terms which differ not in substantial meaning but only in origin; cf. Fritzsche, Romans, vol. iii., p. 270f; (Trench, § xci.)) are found conjoined: Matthew 24:24; Mark 13:22; John 4:48; Acts 2:19, 43; Acts 4:30; Acts 5:12; Acts 6:8; Acts 7:36; Acts 14:3; Acts 15:12; Romans 15:19; 2 Thessalonians 2:9, (Deuteronomy 28:46; Deuteronomy 34:11; Nehemiah 9:10; Isaiah 8:18; Isaiah 20:3; Jeremiah 39:20 (Jer. 32:20); Wis. 8:8 Wis. 10:16; Polybius 3, 112, 8; Philo, vit. Moys. 1:16; Josephus, Antiquities 20, 8, 6; b. j. prooem. 11; Plutarch, Alex. 75; Aelian v. h. 12,57); with καί δυνάμεσιν added, 2 Corinthians 12:12; Hebrews 2:4; σημεῖα καί δυνάμεις, Acts 8:13; δυνάμεις καί τέρατα καί σημεῖα, Acts 2:22; διδόναι σημεῖα (see δίδωμι, B. II. 1 a.): Matthew 24:24; Mark 13:22 (here Tdf. ποιεῖν, σημεῖον, see ποιέω, I. 1 c.); σημεῖα are said γίνεσθαι διά τίνος in Acts 2:43; 4:(Acts 4:16),Acts 4:30; Acts 5:12; 14:3; 15:12 (here ποιεῖν σημεῖον, see above); τό σημεῖον τῆς ἰάσεως, the miracle, which was the healing, Acts 4:22.

BLB Scripture Index of Thayer's