In the old days, when the only means of transport were horses, there were many difficulties in communication between people, in commerce, and in life generally.

commerce 由前缀 com-（表示"共同"）和词根 merce（来自拉丁语 merx，意为"商品"）组成，字面意思是"共同交易商品"，即"商业、贸易"的意思。这个词特指大规模的商品买卖活动。