jer

noun2

1. •
   either of the Proto-Slavic lax vowels /ɪ/ (front jer, ь) and /ʊ/ (back jer, ъ), which in Late Common Slavic were reduced in certain positions to ultrashort vowels [ɪ̆] and [ʊ̆] (weak jers) and then eventually lost.
2. •
   Clipping of jerfalcon.