Probably from 'uwth (in the sense of appearing); a signal (literally or figuratively), as a flag, beacon, monument, omen, prodigy, evidence, etc. -- mark, miracle, (en-)sign, token.
see HEBREW 'uwth
H226. oth
אוֺת noun masculine79 Exodus 4:8 (feminineJoshua 24:17) sign (Arabic , plural , Aramaic אָתָא, ) — ׳א Genesis 4:15 +; construct 9:12 +; plural אוֺתוֺת Exodus 4:9 +?
1 sign, pledge, token Genesis 4:15 (J); אֱמֶת אוֺת true, token Joshua 2:12 (J); of blood of passover Exodus 12:13 (P); לְטוֺבָה אוֺת token for good Psalm 86:17; pledges, assurances of travellers Job 21:29.
2 signs, omens promised by prophets as pledges of certain predicted events 1 Samuel 10:7, 9 + 10:1 where ׳א insert ᵑ9 ᵐ5, see We Dr; especially phrase לְ הָאוֺת זֶה Exodus 3:12; 1 Samuel 2:34; 14:10; 2 Kings 19:29; Jeremiah 44:29; Isaiah 7:11, 14; probably also 44:25 (of false prophets).
3 sign, symbol of prophets Isaiah 8:18 compare Ezekiel 4:3.
4 signs, miracles, as pledges or attestations of divine presence & interposition Exodus 4:8 (twice in verse); 4:9 (J) 7:3 (P) 8:19 (J) Psalm 74:9; 2 Kings 19:29; 20:8-9, = Isaiah 37:30; 38:7, 22; with עָשָׂה Exodus 4:17, 30; Numbers 14:11, 22; Joshua 24:17 (all J E) Deuteronomy 11:3; Judges 6:17; with צִוָּה Exodus 4:28 (J); with שִׁית 10:1 (J); with שִׂים 10:2 (J) Psalm 78:43; Isaiah 66:19; וְהַמּוֺפֵת הָאוֺת (see מוֺפֵת) Deuteronomy 13:3; compare 28:46; Isaiah 20:3; ׳א מ ׳אוֺ Deuteronomy 13:2; וּמוֺפְתִים אוֺתוֺת 4:34; 7:19; 26:8; 29:2; Jeremiah 32:31; with נָתַן Deuteronomy 6:22; Nehemiah 9:10; with שִׂים Jeremiah 32:20; Psalm 105:27; with שָׁלַח Deuteronomy 34:11; Psalm 135:9.
5 signs, memorials, stones from Jordan Joshua 4:6 (J); metal of censers Numbers 17:3 (P); Aaron's rod Numbers 17:25 (P); ׳א עוֺלָם Isaiah 55:13 probably also Ezekiel 14:8 ("" מָשָׁל); signs on hands, etc., Exodus 13:9, 16 (J) = Deuteronomy 6:8; 11:18, probably belong here; also memorial pillar in Egypt Isaiah 19:20.
6 sign, pledge of convenant, ׳א הַבְּרִית (see ברית) e.g. rainbow, of Noachian convenant Genesis 9:12-13, 17 (P); circumcision, of Abrahamic convenant 17:11 (P); the sabbath Exodus 31:13, 17 (P); Ezekiel 20:12, 20.
7 ensigns, standards Numbers 2:2 (P) Psalm 74:4.
8 signs, tokens of changes of weather & times Genesis 1:14 (P; of heavenly luminaries) הַשָּׁמַיִם אוֺתוֺת Jeremiah 10:2 (changes of the heavens as omens to frighten the nations) compare Psalm 65:9.