ы

Etymology 1
Like many Cyrillic letters, originally the letter "y"/"yery" was formed from a ligature: "ꙑ", formed from "ъ" and "і" (formerly written either dotless or with two dots (see "ї")) or "и", whose former letterform resembled "н". In medieval manuscripts, it is almost always found as "ъі" or "ъи". Once the letters "ъ" and "ь" subsequently lost their values as vowels in the Slavic languages, the current simplified form "ы" evolved.

Interjection

 * 1)  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.
 * 2)  ы? as a closing clause: Understand? Agree?