An eyedropper is a small tube with a squeezable rubber bulb at one end, used to pick up and release tiny amounts of liquid one drop at a time. When you squeeze the bulb and place the tube's tip into liquid, releasing the bulb creates suction that draws liquid up into the tube. Squeeze again, and the liquid comes out in controlled drops.

Scientists use eyedroppers in laboratories to measure precise amounts of chemicals for experiments. Doctors and nurses use them to give liquid medicine to babies or to add drops to someone's eyes. Artists sometimes use eyedroppers to create interesting paint effects by dropping colors onto paper.

The tool gets its name because it was originally designed for putting medicine drops into people's eyes, though now it has many other uses. You might also hear people call it a medicine dropper or just a dropper. In science class, you might use one to add water to a test tube drop by drop, or to transfer small amounts of food coloring when doing experiments about how liquids mix.

Many computer programs use an “eyedropper tool” that works similarly: click on any color in an image, and the tool “picks up” that exact color so you can use it elsewhere in your design.