1. To start happening, functioning, or moving at the same time and pace as someone or something; to become simultaneous. Hey, get in sync with your fellow soldiers! How can we make the audio get in sync with the movie?

2. To share the same or similar goals, ideals, desires, likes, dislikes, etc. with someone; to have the same or similar perspectives or opinions as someone. Throughout the date, it just seemed like she and I got totally in sync about everything we brought up. If your team doesn't get in sync with one another, you're going to have a hard time getting this project done.