1. Literally, to be physically located at the center of something or some place. We're in the middle of the crowd, so it will take us a while to push our way out. Listening to my music, I wandered until I realized I was in the middle of the woods, with no idea which path I took.

2. To be in the midst of, or currently engaged in, something, such as an activity. I'm in the middle of a meeting right now, can I call you back? Then, right in the middle of the concert, he walked offstage.