From Longman Dictionary of Contemporary Englishfence something ↔ off phrasal verbSEPARATEto separate one area from another area with a fence a planting area fenced off from the main garden → fence→ See Verb table
Examples from the Corpus
fence off• Till the boy fell in and they fenced it off.• She lifted it over the fence and set off across the little meadow, gathering speed and thoroughly enjoying it.• Shocked driver Shaun Robinson crashed into a fence, writing off his Capri, but escaped injury.• Back towards the house, a wattle fence divides off the western side of the garden. 