Perceptible means noticeable or able to be detected by your senses. If something is perceptible, you can see it, hear it, feel it, smell it, or taste it, even if just barely.

A perceptible change in temperature means you can feel the room getting warmer or cooler. A perceptible difference between two paint colors means your eyes can detect that they're not quite the same shade, even if they're close. When a teacher's voice has a perceptible edge of annoyance, you can hear the irritation in their tone.

The word often describes things that are subtle but still detectable. A scientist might measure a perceptible increase in pollution levels, meaning instruments can detect the change even though it's small. A coach might notice a perceptible improvement in an athlete's form after weeks of practice.

The opposite is imperceptible, meaning too small or subtle to notice. If your friend grows a single millimeter taller overnight, that change would be imperceptible. But if they grow two inches over the summer, that's definitely perceptible. The line between perceptible and imperceptible is where something crosses from “too small to notice” into “you can actually detect this.”