1620s, "flat, thin tablet, with a hole at one end for the thumb, used by an artist to lay and mix colors," from French palette, from Old French palete "small shovel, blade" (13c.) diminutive of pale "shovel, blade," from Latin pala "spade, shoulder blade," probably from PIE *pag-slo-, suffixed form of root *pag- "to fasten." Transferred sense of "colors used by a particular artist" is from 1882. Palette-knife, originally one used by artists for mixing colors, is attested by 1759.
"flat wooden blade" used as a tool by potters, etc., for shaping their wares, early 15c., from Old French palete, diminutive of pale "spade, shovel" (see palette, which is the more French spelling of the same word). The original sense in English was medical, "flat instrument for depressing the tongue." Meaning "large portable tray" used with a forklift for moving loads is from 1921.
It forms all or part of: Areopagus; appease; appeasement; compact (adj.) "concentrated;" compact (n.1) "agreement;" fang; impact; impale; impinge; newfangled; pace (prep.) "with the leave of;" pacific; pacify; pact; pagan; page (n.1) "sheet of paper;" pageant; pale (n.) "limit, boundary, restriction;" palette; palisade; patio; pawl; pax; pay; peace; peasant; pectin; peel (n.2) "shovel-shaped instrument;" pole (n.1) "stake;" propagate; propagation; travail; travel.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit pasa- "cord, rope," pajra- "solid, firm;" Avestan pas- "to fetter;" Greek pegnynai "to fix, make firm, fast or solid," pagos "pinnacle, cliff, rocky hill;" Latin pangere "to fix, to fasten," pagina "column," pagus "district;" Slavonic paž "wooden partition;" Old English fegan "to join," fon "to catch seize."