Definition from Wiktionary, the free dictionary
See also Appendix:Variations of "i"
ы (lower case, upper case Ы)
- The twenty-ninth letter of the Russian Cyrillic alphabet. Its name is ы (ɨ) or еры (jɛrɨˊ) (obsolete) and it is a vowel that is somewhat like the i in bill with the tongue retracted. It is preceded by Ъ and followed by Ь in the Russian alphabet.
- (Internet slang) lol, used to express laughter. Usually used as "ы-ы-ы", to show the crying sound you make after you were laughing for too long.
- (Internet slang) ы? as a closing clause: Understand? Agree?