2. Adjective. (linguistics) Of a spoken vowel sound, preceded with the ''i'' sound. ¹
3. Adjective. (linguistics Slavic paleography) Denoting a letter representing an iotized vowel, like Russian ?, ?, ?, ? or an early Cyrillic letter originating as a ligature with the Greek iota: (Cyrs ?, ?, ?, ?, ?). ¹
¹ Source: wiktionary.com