From Longman Dictionary of Contemporary Englishpaintboxpaint‧box /ˈpeɪntbɒks $ -bɑːks/ noun [countable] 
AVPa small box containing dry paint that you mix with water
AVPa small box containing dry paint that you mix with waterExamples from the Corpus
paintbox• I carry a pocket size sketchbook and paintbox, or no equipment at all.• In his haste to leap out of the way Vincent dropped and broke his paintbox.• Below is a Gothic fantasy of plunging gorges and isolated mesas - flat tablelands with steep edges - all in paintbox colours.• Place on the cake drum next to the paintbox.• The whole world is your paintbox, and nothing pleases you more than to contemplate exquisite, natural things. 