A batch is a group of things made, processed, or dealt with at the same time. When your mom bakes cookies, she might make one batch in the morning and another batch after lunch. Each batch comes out of the oven together as a set.

Factories produce cars in batches, making hundreds of the same model before switching to build a different one. A teacher might grade a batch of essays over the weekend, working through them as a group rather than one at a time throughout the week. Software companies release updates in batches, fixing multiple problems together instead of sending out changes one by one.

The word carries a sense of efficiency and organization. Instead of doing things one at a time, you handle them in sensible groups. A baker doesn't make cookies one by one; she prepares a whole batch at once. A factory doesn't paint each toy car individually; it paints an entire batch together.

You'll also hear batch used for groups of people, especially in formal contexts: “The first batch of students graduated in 1952.” Here it simply means a group that started or finished together, moving through a process at the same time.