From Wikipedia, not found in the general dictionary, A ]fishing lure is an object attached to the end of a which is designed to resemble and move like the prey of a The purpose of the lure is to use movement, vibration, and colour to catch the fish's attention so it bites the hook. Lures are equipped with one or more single, double, or treble hooks that are used to hook when they attack the lure.

In modern usage in the USA, I think a lure is generally felt to be an object of sufficient weight, that when propelled by a fishing rod, will have sufficient momentum to pull line from the reel throughout the flight of the lure. A fly on the other hand relies on the momentum of the line to propel it through its flight.