Definitions for "Tankoubon"
Small paperback books which contain many issues of a manga series.
collections of manga roughly equivalent to the North American trade paperback editions that collect single issues into one publication. Tankoubon tend to be smaller, such as a 7"x5" format.
(単行本) - single volume which collects multiple chapters of a manga series. In Japan, magazines containing chapters from many different manga series are published regularly, usually weekly or monthly. If a series is popular, groups of chapters will later be republished in small paperback volumes (somewhat similar to trade paperbacks or graphic novels in the USA).