The Proto-Turkic word *bük
Word *bük
Meaning to bow, bend, curve
Synonyms *kadɨr-, *kɨjĺ-

Comments
S. A. Starostin, A. V. Dybo, O. A. Mudrak - An Etymological Dictionary of Altaic Languages, 2003, Brill

Other words that might be of interest
*eg- ‘to bend’, *kaŋïr ‘to bend’