To concur means to agree with someone or to share the same opinion. When a teacher asks if anyone disagrees with a conclusion and you concur, you're saying you think the same way. If your friend suggests getting pizza for lunch and you concur, you're on board with that plan.

The word carries a slightly formal tone. You might simply say “I agree” in casual conversation, but concur appears often in official settings. When judges concur on a court decision, they all reach the same conclusion. Scientists might concur that an experiment's results support a particular theory. A doctor seeking a second opinion hopes the other physician will concur with the diagnosis.

The word can also describe things happening at the same time, though this meaning is less common. Two events can concur if they occur simultaneously. Two concurrent events occur simultaneously, like having soccer practice and piano lessons scheduled at the same time on the same day.