Yeru or Eru, usually called Y in modern Russian or Yery or Ery historically and in modern Church Slavonic, is a letter in the Cyrillic script. It represents the close central unrounded vowel after non-palatalised (hard) consonants in the Belarusian and Russian alphabets, and after any consonant in most of Rusyn standards, where it represents the unrounded close-mid back unrounded vowel sound.

The Cyrillic script, Slavonic script or simply Slavic script is a writing system used for various languages across Eurasia. It is the designated national script in various Slavic, Turkic, Mongolic, Uralic, Caucasian and Iranic-speaking countries in Southeastern Europe, Eastern Europe, the Caucasus, Central Asia, North Asia, and East Asia, and used by many other minority languages.