グラゴル文字
A yer is either of two letters in Cyrillic alphabets: ъ (ѥръ, "jerŭ") and ь (ѥрь, "jerĭ"). The Glagolitic alphabet used, as respective counterparts, the letters (Ⱏ) and (Ⱐ). They originally represented phonemically the "ultra-short" vowels in Slavic languages, including Old Church Slavonic, and are collectively known as the yers.