Translit
Writing Cyrillic with Latin keys.
Where it came from
Translit maps Cyrillic letters to Latin ones, born from necessity: early Russian keyboards and SMS only had Latin keys, so people spelled Russian with Latin letters (привет → privet).
Formal systems exist too — GOST and ISO transliteration — for passports and library catalogs. The casual version is just what feels right to a typist.
How it works
There is no single table: "ч" might be "ch" or "4", "ш" might be "sh" or "6". UWC uses a common Russian↔Latin mapping so you can convert both ways in the browser.
Handy for recovering text typed in translit, or generating a Latin spelling from Cyrillic without a dictionary.