Or (shortened) ethan {ay-thawn'}; from an unused root (meaning to continue); permanence; hence (concrete) permanent; specifically a chieftain -- hard, mighty, rough, strength, strong.
Englishman's Concordance
1) perpetual, constant, perennial, ever-flowing 1a) ever-flowing (of a stream) 1b) permanence, permanent, enduring (figuratively) Part of Speech: adjective A Related Word by BDB/Strong’s Number: from an unused root (meaning to continue) Same Word by TWOT Number: 935a
Brown-Driver-Briggs
I. אֵיתָן, אֵתָןadjectiveperennial, ever-flowing, figurative permanent, as substantive steady flow, permanence; — absolute אֵיתָןGenesis 49:24 8t.; אֵתָןJob 33:19; suffix אֵיתָנוֺExodus 14:27; plural אֵיתָנִיםJob 12:19; אֵתָנִים1 Kings 8:2; Micah 6:2; (in form, an 'elative,' Ew§ 162 b = Arabic comparative and superlative); —
1ever-flowing (opposed to אַכְזָב), נַחַל אֵיתָןAmos 5:24 an ever-flowing wady, Deuteronomy 21:4 (see Dr); as substantive in נַהֲרוֺת אֵיתָּןPsalm 74:15rivers of steady flow; as substantive also Exodus 14:27 (J), the sea returned לְאֵיתָנוֺ to its steady flow, יֶרַת הָאֵיתָנִים1 Kings 8:2 month of steady flowings = 7th mo., Oct.-;Nov. (post-Biblical Tisri).
2 figurative permanent, enduringגּוֺי אֵיתָן הוּאJeremiah 5:15, i.e. a nation whose numbers never dwindle or fail, imperishable, ׳וְרִיב עֲצָמָיו אJob 33:19 Kt the strife of his bones is constant, Genesis 49:24 his bow abode ׳בְּא as an enduring, firm, one, מוֺשָֽׁבְךָ׳אNumbers 24:21 ("" שִׂים בַּסֶּלַע), נְוֵה אֵיתָןJeremiah 49:19 = Jeremiah 50:44 an abode of permanency (of Edom, and Babylon, suddenly depopulated by foe, figured as lion); האיתנים מוסדי ארץMicah 6:2 ye ever-enduring ones, the foundations of the earth (but read probably with We הַאֲזִינוּ), Job 12:19אֵיתָנִים יְסַלֵּף he subverteth them that are firmly seated (i.e. men established in hereditary offices or dignities). Very uncertain is Proverbs 13:15דֶּרֶךְ בִּגְדִים אֵיתָן, perhaps firm, hard, rugged (Ew De Hi Now according to Str. the text is corrupt).
Genesis 49:24 HEB: וַתֵּ֤שֶׁב בְּאֵיתָן֙ קַשְׁתּ֔וֹ וַיָּפֹ֖זּוּ NAS: remained firm, And his arms KJV: abode in strength, and the arms INT: remained firm his bow were agile
Exodus 14:27 HEB:לִפְנ֥וֹת בֹּ֙קֶר֙ לְאֵ֣יתָנ֔וֹ וּמִצְרַ֖יִם נָסִ֣ים NAS: returned to its normal state at daybreak, KJV: returned to his strength when the morning INT: appeared daybreak normal Egyptian were fleeing
Numbers 24:21 HEB:מְשָׁל֖וֹ וַיֹּאמַ֑ר אֵיתָן֙ מֽוֹשָׁבֶ֔ךָ וְשִׂ֥ים NAS: Your dwelling place is enduring, And your nest KJV: and said, Strong is thy dwellingplace, INT: his discourse and said is enduring your dwelling is set
Deuteronomy 21:4 HEB:אֶל־ נַ֣חַל אֵיתָ֔ן אֲשֶׁ֛ר לֹא־ NAS: to a valley with running water, which KJV: the heifer unto a rough valley, INT: to A valley running which has not
Job 12:19 HEB:כֹּהֲנִ֣ים שׁוֹלָ֑ל וְאֵֽתָנִ֣ים יְסַלֵּֽף׃ NAS: And overthrows the secure ones. KJV: and overthroweth the mighty. INT: priests barefoot the secure and overthrows
Job 33:19 HEB:ק) עֲצָמָ֣יו אֵתָֽן׃ NAS: on his bed, And with unceasing complaint KJV: of his bones with strong [pain]: INT: adversary his bones unceasing
Psalm 74:15 HEB:ה֝וֹבַ֗שְׁתָּ נַהֲר֥וֹת אֵיתָֽן׃ NAS: You dried up ever-flowing streams. KJV: thou driedst up mighty rivers. INT: dried streams ever-flowing
Proverbs 13:15 HEB:וְדֶ֖רֶךְ בֹּגְדִ֣ים אֵיתָֽן׃ NAS: of the treacherous is hard. KJV: of transgressors [is] hard. INT: the way of the treacherous is hard
Jeremiah 5:15 HEB:יְהֹוָ֑ה גּ֣וֹי ׀ אֵיתָ֣ן ה֗וּא גּ֤וֹי NAS: the LORD. It is an enduring nation, KJV: the LORD: it [is] a mighty nation, INT: the LORD nation is an enduring he nation
Jeremiah 49:19 HEB:אֶל־ נְוֵ֣ה אֵיתָן֒ כִּֽי־ אַרְגִּ֤יעָה NAS: against a perennially watered pasture; KJV: against the habitation of the strong: but I will suddenly INT: against pasture A perennially in an instant
Jeremiah 50:44 HEB:אֶל־ נְוֵ֣ה אֵיתָן֒ כִּֽי־ אַרְגִּ֤עָה NAS: of the Jordan to a perennially watered pasture; KJV: unto the habitation of the strong: but I will make INT: over pasture to a perennially in an instant
Amos 5:24 HEB:וּצְדָקָ֖ה כְּנַ֥חַל אֵיתָֽן׃ NAS: And righteousness like an ever-flowing stream. KJV: and righteousness as a mighty stream. INT: and righteousness stream an ever-flowing
Micah 6:2 HEB:רִ֣יב יְהוָ֔ה וְהָאֵתָנִ֖ים מֹ֣סְדֵי אָ֑רֶץ NAS: of the LORD, And you enduring foundations KJV: controversy, and ye strong foundations INT: to the indictment God enduring foundations of the earth