BookCrossing is defined as "the practice of leaving a book in a public place to be picked up and read by others, who then do likewise." The term is derived from bookcrossing.com, a free online book club which was founded to encourage the practice, aiming to "make the whole world a library."

“图书漂流”指的是“将一本书留在公共场所，等待其他人捡走阅读，捡走书的人读后也会照做”。这种说法来源于bookcrossing.com网站，这是一个免费的网上读书俱乐部，建立的目的就在于鼓励这种行为，旨在“将全世界变成一个图书馆”。

The 'crossing' or exchanging of books may take any of a number of forms, including wild-releasing books in public, or direct swaps with other members of the websites. The community aspect of BookCrossing.com has grown and expanded in ways that were not expected at the outset, in the form of blog or forum discussions, mailing lists and annual conventions throughout the world. 

图书的“漂流”与交换有多种形式，包括将图书随意留存在公共场所，或者与网站读者直接交换图书，等等。BookCrossing.com网站的社区层面的意义不断发展，这是网站建立之初人们没有想到的，比如博客或论坛讨论，邮件列表以及遍布全球的年度会议。