A clicker is a small handheld device that makes a distinct clicking sound when you press it. The most common type is used in dog training: when a dog does something right, the trainer clicks the device and gives the dog a treat. The dog learns to associate that sharp click sound with doing something good, which helps teach new behaviors faster than words alone.

Teachers sometimes use clickers in classrooms too, but these work differently. Students each get a clicker with buttons, and when the teacher asks a multiple-choice question, everyone clicks their answer. The teacher's computer instantly shows how many students chose each option, which helps them know if the class understands the material or needs more explanation. This kind of classroom clicker is sometimes called a student response system.

The word can also describe the remote control for a garage door opener, or really any device you click to make something happen. If your mom or dad asks you to “grab the clicker” while watching TV, they probably mean the remote control, since you click its buttons to change channels.