Also found in: Wikipedia.
A short, lightweight Japanese jacket or robe having wide straight sleeves and an open front, often fastened with ties.
[Japanese happi, alteration of earlier hampi : han, half (from Early Middle Chinese panh) + -pi, combining form of hi, arm (from Early Middle Chinese pjiəh, pjih), perhaps influenced by Japanese happi, a cloth placed by a monk over a chair while performing a memorial service, from earlier Japanese hafuhi : hafu, dharma (Modern Japanese hō) + hi, a kind of garment.]
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.