Accordance means agreement or harmony with something, especially rules, standards, or expectations. When something happens in accordance with a plan, it follows that plan exactly. When a school operates in accordance with safety regulations, it obeys those rules carefully.

You'll often see this word in formal contexts. A judge might rule in accordance with the law, meaning the decision follows what the law requires. A ceremony might proceed in accordance with tradition, meaning it respects established customs. Scientists conduct experiments in accordance with proper methods to ensure their results are trustworthy.

The word suggests careful attention to following something correctly and precisely. If your teacher says to complete an assignment in accordance with the instructions, she means you should follow every part of the directions exactly as written.

You might also hear people say two things are in accordance, meaning they match or align with each other. When someone's actions are in accordance with their values, they're living consistently with what they believe is right.