1680s, "engaging in trade," from commerce + -al (1). Meaning "done for the sake of financial profit" (of art, etc.), "prepared for the market or as an article of trade" is from 1871. Meaning "paid for by advertisements" (in reference to radio, TV, etc.) is from 1932. Related: Commercially.
"an advertisement broadcast on radio or TV," 1935, from commercial (adj.). Earlier as a noun it was short for commercial traveler (1855).