Question: What is the "universal" Church?

From the Catechism para. 830-831:

The word "catholic" means "universal," in the sense of "according to the totality" or "in keeping with the whole."

The Church is catholic because she has been sent out by Christ on a mission to the whole of the human race (cf. Matt 28:19): All are called to belong to the new People of God. This People, therefore, while remaining one and only one, is to be spread throughout the whole world and to all ages in order that the design of God's will may be fulfilled: He made human nature one in the beginning and has decreed that all his children who were scattered should be finally gathered together as one....