gou ‧ ache /ɡʊˈɑːʃ, ɡwɑːʃ/ BrE AmE noun
[ Date: 1800-1900 ; Language: French ; Origin: Italian guazzo 'small pool' , from Latin aquatio 'act of bringing water' ]
1 . [uncountable] a method of painting using colours that are mixed with water and made thicker with a type of glue
2 . [countable] a picture painted in this way