商 is a bound form (b.f.) that never stands alone in modern Chinese — you always use it as part of a multi-character word. Its major senses include commerce/trade (商业, 商人), discussion/consultation (商量, 商议), the mathematical concept of quotient (智商, 情商), and the Shang dynasty (商朝, c.1700-1045 BC) which is also a common surname. Context determines which meaning is active.