1 the best and most expensive seats or accommodation on a train, ship, etc （火车、轮船等的）头等座位，头等舱

2 the quickest form of mail （优先投递的）第一类邮件: First class costs more. 第一类邮件收费较高。

3 the highest standard of degree given by a British university （英国大学）一等学位 first class adv to travel first class 乘头等舱旅行 · I sent the letter first class on Tuesday. 我在星期二以第一类邮件寄了那封信。