Is it ensure, insure, or assure?
1550s, past participle adjective from limit (v.); as a stand-alone for limited express train, by 1883. Limited edition is from 1920; limited monarchy from 1640s; limited war is from 1948. In British company names, Limited (abbrev. Ltd.), 1855, is short for limited liability company, one in which the liability of partners is limited, usually to the amount of their capital investment.