[uncountable]a way of travelling on a train or ship that costs less and is less comfortable than first class. In the UK this is now usually called standard class.（火车的）二等车厢；（船的）二等舱Topics Transport by bus and trainb1
[uncountable](in the UK) the class of mail that costs less and takes longer to arrive than first class第二类邮件（在英国投递较第一类邮件慢，邮资也较低）
Second class is cheaper.二等便宜。
[uncountable](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）
[uncountable, singular]the second highest standard of degree given by a British university, often divided into upper second class and lower second class二等学位（英国大学学位等级）Topics Educationc2