Clauson (1972)
An etimological dictionary of pre-thirteenth-century Turkish
p. 523-524
tegri: a very old word, prob. pre-Turkish, which can be traced back to the language of the Hsiung-nu, m B.C., if not earlier. It seems originally to have meant ‘the physical sky’, but very early acquired religious overtones and came to mean ‘Heaven’ as a kind of impersonal deity, the commoner meaning in the earlier texts.
It was the normal word for ‘God’ in Man. and Bud. texts and was retained in this sense in the Moslem period, although it is rare in KB, where the normal word for ‘God’ is bayat, and was later largely displaced by l.-w.s like Allāh and xudāy.
An early l.-w. in Mong. as teŋgeri (Haenisch 148, Kozv. 1697; but often spelt tŋri, as in Turkish, in religious texts and always dèŋri in the hP’ags-pa texts). S.i.a.m.l.g., in NE often in the Mong. spelling, in SW Az., Osm., Tkm. taŋrı:, this is prob. an old Oğuz pronunciation, but it is impossible to discover when the change occurred; a l.-w. in Pe. see Doerfer II 944, where it is discussed at great length.
Türkü VIII teŋgri: is common; in üze: kök tegri: asra: yağız yer kılındukda: ‘when the blue sky above and the brown earth below were created’ IE 1, II E 2 it clearly has a physical sense, but this is rare; it is more often used in a religious sense, e.g. tegri: yarlikadukı:n üçü:n ‘because Heaven so commanded’ I S 9, II N 7, and even as a sort of tribal deity in üze: Türkü teŋri:si: ‘the Heaven of the Türkü on high' IE 11, II E 10: vm ff.
teŋgri: is fairly common in IrkB, both in a physical sense, e.g. (a hawk) tegri:din (sic) kodi: . . . kapmı:ş ‘swooped down from the sky’ 44; and in a religious sense, e.g. ala: atlı:ğ yol (or yul) tegri: men ‘I am the god of the road (or the spring) riding on a dappled horse’ 2: Man. tegri (consistently spelt trjri in all scripts) is very common; in yer tegri yok erken ögre ‘when earth and heaven did not yet exist’ Chuas. 162-3 it has a physical sense, but nearly always means ‘God’ or ‘divine’: Yen. üze: tegri: yarlıkadı: Mai. 32, s; a.o.(?) do. 36, 2: Uyğ. via ff. Man.-A tegri (in all Uyğ. texts consistently spelt tijri) is common; (they first created) on kat kök tegrig ‘the blue heavens in ten layers’ M I 14, 6-7—tegri Mam burxan tegri yerigerü bardukinta ‘since the divine Prophet Mani went to the heavenly country’ do. 12, 13-14; and many 0.0. meaning ‘God, divine’: Man. teŋgri ‘God, divine’ is common: Bud. ditto but yer tegri törümişte ‘when earth and heaven were created’ PP 5, 8; a.o. do. 18, 2 (tiipir-): Civ. tegri is more often used in a physical sense, e.g. tegri kapığı açıltı ‘heaven’s gate has been opened’ TT I 144: O. Kir. ix ff. kök tegri:de: kiin ay ‘the sun and moon in the blue sky’ Mai. 10, 3; 45, 5 and tegri: elim ‘my divine realm’ do. 3, 2; 14, 3 etc. are included in the list of ‘partings’ in funerary inscriptions: Xak. xi tegri: Allâh 'azza wa calla ‘God, to Him belongs glory and power’ (prov. see tapuğsa:k; verse). The unbelievers (al-kafara) call the sky (al-samâ’) tegri:, and also anything which is great in their eyes, like a big mountain or big trees, and for this reason they worship such things Kaş. Ill 376; many O. 0. translated ‘God’: KB the standard words for ‘God’ are bayat and uğan but tegri occurs in 44, 92, 6176 (erki:): xm(?) At. tegri is not used in the text but occurs in glosses on idim and uğan; Tef. tagrı(-ğa) ‘God’ 285, 289 (teıjri): xiv Muh. Alldhu l-qazvi ‘almighty God’ tegri: Mel. 12, 15; u:ğa:n tegri: Rif. 87; Allah ta'âlâ tegri: 44, 8; 137: Çağ. xv ff. tegri (spelt) canâb-i bârı ta'âlâ ‘the Creator’ San. 202r. 26 (quotn.): Xwar. xm(?) kök (VU) tegri ‘blue sky’ Og. 60, etc.; tegrini calbarğuda ‘while praying to God’ do. 50: xiv tagri(-ka)/tegri(-ke) Qntb 170; (VU) MN 1 : Kom. xiv ‘God’ tegri common CCI, CCG; Gr. 241 (quotas.): Kip. xm Allâh subhânuhu wa ta'âlâ tegri: (and in a dialect which only a few people know uğa:n) Hon. 3, 12: xiv tegri: (‘with -g-’) Allah İd. 40; Allâh calla dikruhu tegri: Bid. 2, 9: xv li- -acali'llâh ‘for God’s sake’ teğri: üşün (sic with -ğ- for -rj-) Kav. 43, 8; Allah tegri Tub. 3b. 10; 41b. 6: Osm. xiv ff. the pronunciation was prob. always tagn, the A.N. tagrilik is noted in xv TTS III 667.