Ave. is not a word you say. It is the written short form of Avenue, used in addresses, on envelopes, maps, and street signs, especially in the United States, Canada, and Britain. You write 5th Ave. or Maple Ave. When you speak, you say Avenue. An avenue is often a wide road, sometimes with trees, though actually in many cities Avenue is just a name and the road may look like any other street. The full stop (period) marks the shortening. This Ave. has nothing to do with church Latin Ave (as in Ave Maria, 'Hail Mary'), which is a different Ave from a different language and is not short for Avenue.