Here's a breakdown:
* te: the (definite article)
* katoa: all, whole, entire
You can also use "tēnei katoa" which literally translates to "all of this" and is used to refer to "everyone here".
Examples:
* Te katoa e hiahia ana kia haere? (Everyone wants to go?)
* Tēnei katoa e mohio ana ki tēnei take. (Everyone here knows about this matter.)