Cyrillic Small Letter U

It usually represents the vowel “oo,” as in “boot.” The exact pronunciation depends on the language; the letter is commonly transliterated as u, not y.

It began as оу, a two-letter spelling in Old Church Slavonic (the medieval church language Cyrillic was created to write), copied from Greek ου for the same vowel. Scribes joined the pair into forms such as ѹ and ꙋ, and shortening left у. The shape itself traces to Greek upsilon, which Cyrillic also borrowed separately as Izhitsa, Ѵ.

Is Cyrillic у the same character as Latin y?

No. They can look alike, but they belong to different scripts.

Many fonts draw lowercase у and Latin y identically. In usernames, domains, passwords and search, one cannot stand in for the other: a word mixing both scripts fails to match or can impersonate another name. Check which script a y-shaped letter belongs to instead of trusting its shape.