Noun:

1. not the highest rank in a classification

2. not the highest quality in a classification

3. a class of accommodations on a ship or train or plane that are less expensive than first class accommodations

Adverb:

1. by second class conveyance;

   "we traveled second class"
   

cabin classn.特别二等舱；(介于头等舱与二等舱之间)

economy class经济舱

1. A two-week return to Washington, second class, please.
   为期二周返回华盛顿，二等。
2. A second- class letter is slower than a first- class.
   二等信件比一等信件慢点。
3. Preferred forms of transportation run the gamut from rickshaws to first class Emirate Airways cabins.
   我更喜欢全程坐着人力车而不是坐在阿联酋航空公司的一等舱里。
4. Flights are horribly crowded, food and beverage service has deteriorated in first class and virtually disappeared in coach, and the incidence of mislaid baggage has increased.
   每一航班都异常的拥挤，餐饮服务在一等舱已退化，在经济舱里实际上已经消失，加之遗失行李的事件也在增加。