studdingsail

stud·ding·sail

 (stŭn′səl, stŭd′ĭng-sāl′)
n.
Any of several supplementary sails set from extensions of the yards of a square-rigged ship in light winds.

[Origin unknown.]

studdingsail

(ˈstʌdɪŋˌseɪl) (ˈstʌnsəl)
n
(Nautical Terms) nautical a light auxiliary sail set outboard on spars on either side of a square sail. Also called: stunsail or stuns'l
[C16: studding, perhaps from Middle Low German, Middle Dutch stōtinge, from stōten to thrust; related to German stossen]