Clauson (1972)
An etimological dictionary of pre-thirteenth-century Turkish
p. 350-351
beŋgü: (?beŋgö)
‘eternal, everlasting’. An early l.-w. in Mong. as möŋke (Haenisch 112 möngke, but the modern pronunciation (Haltod 508) is möŋke). S.i.a.m.l.g. except SW. The NE forms möŋkü R IV 2131 and Tuv. möŋge are reborrowings fr. Mong., elsewhere normally meŋgi or the like; to be carefully distinguished fr. beŋi: with which it is easily confused in some scripts. Türkü viii beŋgü: taş ‘memorial (lit. ‘everlasting’) stone’ I S 11, II N 8; I S 12 (biti:-), II N 15; a.o. I S 8, II N 6 (1 é:l): viii ff. Man. meŋigü teŋri yerin ‘the country of the eternal gods’ Chuas. I 15; a.o. do. I 29; M III 15, 2 (i); meŋü Zrwa ‘the eternal god Zurwan’ M III 5, 8; Yen. beŋgü:min tike: berti: ‘he erected my memorial’ Mal. 28, 4; same phr. but beŋü:si: do. 30, 3; o.o. 27, 8; 33, 3; 36, 3 (all beŋgü:); 39, 1; 48, 6 (both beŋkü:); meŋkü: 39, 5: Uyğ. viii ff. Man.-A meŋigü M I 11, 19, etc. (ögrünçlüg); o.o. do. 11, 16; 12, 11: Chr. meŋü teŋri U I 7, 5: Bud. yertinçüdeki özüg yaşığ meŋü sakındıŋızlar ‘you thought that life (Hend.) in (this) world is everlasting’ TM IV 252, 4; Meŋü as a P.N. Pfahl. 12, 19: O. Kır. ix ff. beŋü:sü: (sic?) Mal. 9, 3; a.o. 42, 5(?); beŋgü:min do. 13, 5; a.o. 24, 2; beŋkü:min 20, 1: Xak. xi meŋgü: al-şay’u’l-xālid wa’l-xulūd ‘anything eternal; eternity’; both common N. (ism) and Dev. N. (maṣdar); one says meŋgü: aju:n dāru’l-xulūd ‘the eternal (i.e. future) world’ Kaş. III 378 (verse): KB meŋü (so spelt) ‘eternal’ is common 10, 113, 115, etc.: xiii(?) Tef. meŋü ditto 223: Xwar. xiv ditto Qutb 110; MN 121; meŋgü Nahc. 281, 2-3: Kom. xiv meŋgü/meŋü/meŋi CCG; Gr. 164: Kıp. xiii dāma ‘to continue, endure’ meŋü kal- (mis-spelt kol-) Hou. 40, 3: xiv meŋü: su: mā’u’l-ḥayāt ay mā’u’l-dawām ‘the water of life, that is, the water of eternity’ İd. 89.