1. To barricade, erect a barrier around, or deny access to something. Remember to bar off the front and back doors when you leave the building at night. The school threatened to bar off Internet access for students who use it to look at unrelated or inappropriate material.

2. In agriculture, to plow a furrow on either side of a row of plants so that their roots sit atop a high, narrow bed of soil. Make sure you bar off those rows of new seedlings first thing this morning.