Binary means having two parts, options, or states. In everyday language, a binary choice is one where you pick between exactly two possibilities, like yes or no, on or off, true or false.

When something is binary, there's no middle ground or third option. A light switch works in a binary way: it's either up or down, and the light is either on or off.

In computers, binary means the number system that uses only 0 and 1. Every piece of information a computer processes, from videos to text messages, gets translated into long strings of zeros and ones. This might seem limiting, but computers can represent anything using just these two digits. The binary number 101, for instance, equals five in our regular counting system. Think of it like Morse code, which creates every letter using just dots and dashes. Computers use binary because electronic circuits easily represent two states: electricity flowing (1) or not flowing (0).

Scientists use “binary star system” to describe two stars orbiting each other, and chemists talk about binary compounds made from two elements. Whenever you see binary, look for the pair, the two-part system, or the either-or choice at the heart of what's being described.