An indicator is something that gives you information about a larger situation, like a clue that helps you understand what's really going on. Think of a thermometer: the rising red line is an indicator of temperature. The thermometer doesn't create heat or cold, it just shows you what's happening.

In science class, you might use a pH indicator, a special liquid that changes color to show whether something is an acid or a base. The color change indicates information you couldn't see otherwise.

Indicators appear everywhere in daily life. A friend's frown might be an indicator that something's bothering them. Your grades are indicators of how well you're understanding the material. When economists talk about economic indicators, they mean measurements like unemployment rates or factory production that reveal the economy's health.

Car dashboards are full of indicators: lights and gauges that tell you about fuel level, engine temperature, and speed. A turn signal is literally called a “turn indicator” because it shows other drivers what you're about to do.

The key thing about indicators is that they're signs pointing toward something else. They help you notice patterns, spot problems early, or understand complex situations by giving you specific, measurable information you can actually observe.