canvas n.

1798, "common hemp," from Cannabis, Modern Latin plant genus named (1728), from Greek kannabis "hemp," a Scythian or Thracian word. That word is also source of Armenian kanap', Albanian kanep, Russian konoplja, Persian kanab, Lithuanian kanapės "hemp," and English canvas and possibly hemp. In reference to use of the plant parts as an intoxicant, from 1848. Related: Cannabic.

also canvasback, 1785 as a type of North American duck, so called for the color of the back. Earlier as an adjective for a type of garment made of expensive stuff in front and cheap canvas in the back (c. 1600); from canvas (n.) + back (n.).

c. 1500, "toss in a canvas sheet," from alternative spelling of canvas (n.). From "toss in a canvas sheet for the purpose of sifting" the meaning was extended figuratively to "shake out, examine carefully" (1520s). From thence (though the image in the sense-shift is less clear) to "solicit votes or test support before an election" (1550s). Compare Old French canabasser "to examine carefully," literally "to sift through canvas." The spelling with a double -s- dates from 16c. and is useful to distinguish it from the other word. Related: Canvassed; canvassing. As a noun, "a soliciting of votes or testing of support," from c. 1610s.