a way of travelling on a train or ship that costs less and is less comfortable thanfirst class （火车的）二等车厢；（船的）二等舱ⓘ In the UK this is now usually called standard class. 在英国目前通称standard class（标准舱位）。
in the UK, the class of mail that costs less and takes longer to arrive than first class 第二类邮件（英国邮件等级，较第一类邮件慢，邮资也较低）◆second-class letters 第二类信件
in the US, the system of sending newspapers and magazines by mail 第二类邮件（美国报刊投递类别）