Thread:Kiadony/@comment-5916303-20150330132211/@comment-1746153-20150430155843

Yes, we've got the same case with the "young woman" as well - девушка for girlfriend/young woman, while the similar девочка refers to a female child specifically (unless it's used in the same vein as "babe"). The diminutive form of подруга, подружка, also refers to a girlfriend when said by a male; between females, both words mean female friend. So it has a lot of nuances.

Oddly, друг can only mean (male) friend, for boyfriend we use парень (literally meaning "guy") or the transcribed version of "boyfriend" (бойфренд).