bolt-on
n.—Gloss: a business or product line acquired by a company in lieu of the company developing that product or expertise for itself. Note: Also as an adjective. «Although Oracle would like to be considered daring, its strategy of growth-by-acquisition has generated a backlash in corporate software circles, where it is sometimes called a bolt-on company.…“A bolt-on is when you buy it rather than build it yourself.”» —“BEA Systems rejects Oracle’s takeover bid” by Tom Abate San Francisco Chronicle (California) Oct. 13, 2007. (source: Double-Tongued Dictionary)