Clauson (1972)
An etimological dictionary of pre-thirteenth-century Turkish
p. 295
D bıçım
N.S.A. fr. biç-; survives only(?) in SW Osm., Tkm. biçim (sic) ‘the cut (of a garment); form, shape, manner’. Xak. xi bi:r biçim ka:ğu:n ‘a slice (şaṭba) of melon’, or something else Kaş. I 395; a.o. I 15, 15.