Explain the term usage of trade.What happens if there is a conflict between the express terms of the contract and trade usage?

In many kinds of businesses,there are customs and practices of the trade that are known by people in the business and that are usually assumed by parties to a contract for goods of that type.Under the Code,the parties and courts may use these trade customs and practices-known as usage of trade-in interpreting a contract.If there is a conflict between the express terms of the contract and trade usage,the express terms prevail.