1. Literally, to follow or maintain the proper rhythm of someone or something else while marching. It was impressive to see so many troops all marching in step during the military parade. The children marched in step with their teacher as they walked to the library.

2. To conform to or act in accordance with someone or something, especially by doing what is considered correct, proper, acceptable, etc. You really need to start marching in step if you want to keep your job as our lead artist—you work for the company, not for yourself. The senator is often criticized for not marching in step with the views of her political party, but that's why so many people across the country love her.