Least costly and least luxurious accommodations, as on a ship.

(价格最便宜,设备最检朴的)三等舱。

Class of mail not exceeding one pound in weight, including books, circulars, and other printed matter not sealed against postal inspection.

【美】第三类邮件(不超过一磅，包括书籍及印刷品、未密封、以备检查)。