From Longman Dictionary of Contemporary Englishbox something ↔ off phrasal verbTBCto separate a particular area from a larger one by putting walls around it We’re going to box off that corner to get extra storage space. → box→ See Verb table
Examples from the Corpus
box off• I wanted all those wonderful colors to collide in ways that could blow your voice box right off.• When he took over the role last year, the box office took off, and the reviews were positively glowing.• The jury box is set off by a walnut rail and descending baubles, round spheres of beautifully grained wood.• So I packed my plastic box, and off I went.• So now I want you and your whole box of tricks off my ship and out of my way.• I stepped back obligingly and let him heft the box up off the floor and carry it to my car.• Some were taking boxes and drums off the lorries. 