Transaction is a technical term (used in contracts or specialized news...) deal is more spoken. Transaction means an exchange (usually money exchanged for goods or fro a service, so its a purchase. But also money that goes from one bank to another ("trans" means across in latin). A deal is more general. It can be an exchange, but also just something two people agree on. It often has a good or bad quality to it. ex: This bank is preparing for a large transaction. If you had not accepted to do that you would have made a better deal...

very different. deal多用在生意上的政治上的交易，比如说你跟人讨价还价，最后同意成交，你就说 deal. 而transaction通常是针对业务事务的交换，对公的，对私的。对私的一般多是情感交流吧。 嘿嘿，这个回答能打几分？