Rectrix

имя существительное [зоология, множественное число] rectrices рулевое перо птицы Синоним(ы): rudder

Большой англо-русский словарь

Rectrix

noun (plural rectrices) Etymology: New Latin, from Latin, feminine of rector one that directs any of the quill feathers of a bird's tail that are important in controlling flight direction — see bird illustration

Merriam-Webster's Collegiate Dictionary