يکا yak-kā P. 1. adj. Single, solitary. 2. s. m. The ace (at cards). 3. A one-horse chaise. 4. A trooper who serves alone. 5. adj. Unique, unequalled. يکا تاز yakkā-tāz, Singly attacking (the foe); the phenix or hero (of the age). يکا سپاهي yakkā-sipāhī, A single soldier.