ding
A small dent or a short bell-like sound.
Ding is a small dent or mark on a surface, usually from something bumping or hitting it. Your bike might get a ding in the fender from leaning it against a wall, or a car door might have a ding from a shopping cart rolling into it in a parking lot. These marks aren't major damage, just minor imperfections that show an object has been used and lived with.
The word also describes a short, sharp ringing sound, like a bell or chime. An oven makes a ding when your cookies are done baking. A timer dings to let you know time's up. Some phones make a ding sound when you receive a text message. This kind of ding is meant to catch your attention without being too loud or jarring.
When you ding something, you're causing that small dent or making that bell-like sound. You might accidentally ding the wall with your backpack, or you can ding a bicycle bell to warn pedestrians that you're coming through.
People sometimes use ding-dong to describe the sound of a doorbell, combining two similar chiming sounds into one friendly announcement that someone's at the door.