when a company that has a contract to use or provide particular products, uses different products instead, especially ones that do not meet the required standards 产品替代（指公司用不同产品代替合同中规定使用或提供的产品，尤指代替不符合规定标准的产品）
when consumers start to buy and use a related but different product from the one they normally buy and use; when producers start to offer a different product 产品替代（指消费者开始购买和使用与惯用产品相关但有区别的产品；生产商开始提供不同的产品）