To close something off means to separate it from other things or people so that they cannot go there. Police closed off about 12 blocks of a major San Francisco thoroughfare for today's march = seal off
close off
التركية النطق
klōs ôf
النطق
/ˈklōs ˈôf/ /ˈkloʊs ˈɔːf/
علم أصول الكلمات
[ 'klOz ] (verb.) 13th century. Middle English, from Old French clos-, stem of clore, from Latin claudere to shut, close; perhaps akin to Greek kleiein to close; more at CLAVICLE.