also: グワッシュ · グアッシュ · グァッシュ
noun
gouache
An opaque watercolor paint, or a painting made with it. Used in art contexts.
from French
彼女はガッシュで風景を描いた。
She painted a landscape in gouache.
水彩 is general watercolor, while ガッシュ is specifically opaque gouache.
Borrowed from French 'gouache'.