Coherent means logical, clear, and making sense. When your teacher asks you to write a coherent paragraph, she wants your sentences to connect smoothly and your ideas to flow in a logical order, not jump randomly from topic to topic.

A coherent explanation is one where each part fits with the others. If you're explaining how to bake cookies, a coherent set of instructions would tell you to mix the ingredients before putting them in the oven, not the other way around. Scientists value coherent theories where all the evidence points in the same direction and doesn't contradict itself.

The opposite of coherent is incoherent. Someone who just woke up from a deep sleep might mumble incoherent words that don't form real sentences. A story that keeps changing its own rules or contradicting what happened earlier would be incoherent.

When someone stays coherent during a crisis, they keep thinking clearly and logically instead of panicking. The word suggests both clarity of thought and the ability to express those thoughts in a way other people can follow and understand.