trade paperback

Short definition from Wiktionary

Noun

1. 1
   A softcover edition of a previously hardcover book, usually produced with the exact same text as the hardcover.
2. 2
   A paperback book that is in one of the standard sizes for small paperbacks, generally for genre fiction.
3. 3
   A type of comic book primarily containing previously published material, traditionally in a periodical format, and bound together as one work, or part of a series itself.