roundup (Noun) — The activity of gathering livestock together so that they can be counted, branded or sold.
roundup (Noun) — A summary list; as in e.g. "a news roundup".
roundup (Noun) — The systematic gathering up of suspects by the police. ex. "a mass roundup of suspects"
roundup (Verb) — Seek out and bring together. ex. "round up some loyal followers"