na·pa cabbage or nap·pa cabbage (n?p??, nä?p?)n. A plant (Brassica rapa subsp. pekinensis) of the mustard family, having an elongated head of overlapping, crinkled, broad-stalked leaves and eaten as a vegetable in eastern Asian cuisine. Also called Chinese cabbage.[Probably Japanese nappa, greens.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.