merchant: [13] Latin merx denoted ‘goods for sale’. From it was derived the verb mercārī ‘trade’ (whose past participle was the source of English market). Mercārī was adapted in Vulgar Latin to mercātāre, whose present participle mercātāns produced the Old French noun marcheant ‘trader’, source of English merchant. Merchandise [13] comes from a derivative of marcheant; and other English descendants of Latin merx are commerce and mercury. => commerce, market, mercury[merchant etymology, merchant origin, 英语词源]