Entry 1 sense Webster, 1913 pe-tsai · IPA 01 n. A plant with an elongated celerylike head of broadstalked leaves used as a vegetable in east Asia. 1. A plant with an elongated celerylike head of broadstalked leaves used as a vegetable in east Asia. Syn. Chinese cabbage, celery cabbage, napa, Brassica rapa pekinensis.