To adjust means to make a small change to something so it works better or fits more comfortably. When you adjust the seat in a car, you move it forward or backward until you can reach the pedals. When you adjust the volume on a speaker, you turn it up or down to just the right level. When you adjust a microscope, you're turning the focus knob until the image becomes sharp and clear.

The word suggests fine-tuning rather than completely changing something. You wouldn't say you're adjusting a broken bicycle when you replace the entire chain; you'd adjust the brakes by tightening a cable slightly, or adjust the seat height by moving it up an inch or two.

People also adjust to new situations, which means getting used to changes over time. When you adjust to a new school, you learn where your classrooms are, figure out the lunch routine, and make new friends. This kind of adjusting takes patience because you're changing your habits and expectations to fit a new environment. A student moving from a loud classroom to a quiet library might need a few minutes to adjust to the different atmosphere and settle into studying.

The noun form is adjustment: “The piano tuner made several adjustments to get each note perfectly in tune.”