名詞 second-class:

1. not the highest rank in a classification
   同義詞：second class
2. not the highest quality in a classification
   同義詞：second class
3. accommodations on a ship or train or plane that are less expensive than first class accommodations
   同義詞：Cabin class, second class

形容詞 second-class:

1. of inferior status or quality

副詞 second-class:

1. by second class conveyance
   同義詞：second class