Discrete means separate and distinct from other things. Each item in a discrete set stands alone and can be counted individually. The buttons on a calculator are discrete: you can count them one by one, and each button is its own separate unit. The students in your classroom are discrete individuals, not a blob of humanity.

Scientists often distinguish between discrete and continuous data. Discrete data comes in distinct units: the number of books on a shelf (you can't have 7.3 books), the count of students in a class, or the dots on a pair of dice. Continuous data, by contrast, flows smoothly: temperature, time, or the exact height of a plant can take any value, including decimals and fractions.

The word appears in many contexts. A discrete category is clearly separated from others. A discrete problem is a single, specific issue rather than part of a larger tangle. When you break a complex math problem into discrete steps, you're separating it into distinct, individual parts that you can tackle one at a time.

Don't confuse discrete with discreet, which means subtle or careful not to attract attention. They sound identical but mean completely different things: discrete things are separated, while discreet actions are quiet and tactful.