/gwahsh, gooh ahsh"/ ; Fr. /gwannsh/ , n. , pl. gouaches /gwah"shiz, gooh ah"shiz/ ; Fr. /gwannsh"/ for 3.
1. a technique of painting with opaque watercolors prepared with gum.
2. an opaque color used in painting a gouache.
3. a work painted using gouache.
[ 1880-85; guazzo place where there is water aquatio, deriv. of aqua water ]