Bakı

Etymology
Baku is long attested under the Perso-Arabic name باکو (Bākū). Early Arabic sources also refer to the city as Bākuh and Bākuya, all of which seem to come from a Persian name. Further etymology is unknown.

A popular etymology in the 19th century considered it to be derived from Persian, compound of +  +. This etymology was first proposed in the 17th century-chronicle.

Another and even less probable folk etymology explains the name as deriving from Baghkuy, from compound of  +  +, meaning "God's town". The name Baghkuy may be compared with Baghdād ("God-given") in which dād is the Old Persian word for "give".

During, the city was spelled in Cyrillic as in Azerbaijani (while the Russian spelling was and still is ). The modern Azerbaijani spelling, which has been using the Latin alphabet since 1991, is ; the shift from the Perso-Arabic letter و (ū) to Cyrillic ы and, later, Latin ı may be compared to that in other Azerbaijani words (e.g. compare in old Perso-Arabic spelling with modern Azerbaijani ) or in suffixes, as و was often used to transcribe the vowel harmony in Azerbaijani (which was also the practice in Ottoman Turkish).