In ecclesiastical use, this refers to someone who belongs to the Roman Catholic Church, considered the largest of the Christian sects.
In non-ecclesiastical use, it derives its English meaning directly from its root, and is currently used to mean the following:
including a wide variety of things, or all-embracing
universal or of general interest
having broad interests, or wide sympathies
inclusive, inviting
Obviously, this tag refers to the first definition. The easiest Catholics to identify are the nuns since they wear black habits. Priests can either wear the cassock or a set of robes for their sermons. The best identifier of a Catholic priest is a crucifix, since just wearing a stole over their robes isn't enough of an indicator of what their beliefs are.
