1. To attach snugly on(to something), creating an audible snap when doing so. All these pieces just snap on, so you can customize your toy robot to look whatever way you like. I bought a webcam that snaps on my monitor to make video calls a bit more manageable.

2. To cause or force something to attach snugly on(to something else), creating an audible snap when doing so. In this usage, a noun or pronoun can be used between "snap" and "in." I just need to snap this final piece on, and my model will be complete! The soldier snapped on a scope and aimed the long-distance rifle at his target.

3. To turn on some electronic device, especially a television or radio. In this usage, a noun or pronoun can be used between "snap" and "on." Would you mind snapping the TV on? My favorite show is on and I want to catch the latest episode. He shuffled over to his armchair and snapped on the radio.