A collection or compilation (used as a suffix indicating a gathered set of works, e.g., -shū as in anthology, collected works).
彼は自分の写真集を出版した。
He published his own photo collection.
図書館で詩集や小説集を探した。
I looked for poetry collections and short story collections at the library.
この全集は著者の論文を全て集めた集だ。
This complete works gathers all of the author's papers.