(Aramaic) from a root corresponding to that of 'Athariym; a place; (adverb) after -- after, place.
see HEBREW 'Athariym
H870. athar
אֲתַר noun masculine place (so Egyptian Aramaic, Nabataean, Palmyrene; ᵑ9; Syriac place; Zinjirli אשר Lzb229f.; Arabic footstep; compare Hebrew אֲשׁוּר and below אֲשֶׁר); — place a. Daniel 2:35 לְהוֺן לָאהִֿשְׁתְּכַח וְכָלאֲֿחַר, Ezra 5:15 עַלאַֿתְרֵהּ יִתְבְנֵא אֱלָהָא וּבֵית, 6:3, 5, 7. Hence
b. בָּאתַר (Daniel 7:6 Baer בָּתַר) after (literally in the track of: so Zinjirli באשר (Cooke160f., 170), Palmyrene, בָּתַר ᵑ9, Syriac ), דְּנָה בָּאתַר after this, 7:6-7, suffix 2:39 וּבָֽתָרָךְ and after thee.
אַתַּ֫רוּ see נתר.