I. cor ‧ don 1 /ˈkɔːdn $ ˈkɔːrdn/ BrE AmE noun [countable]
[ Date: 1700-1800 ; Origin: cordon 'strip of cloth or decorative cord' (16-21 centuries) , from French , from corde ; ⇨ ↑ cord ]
a line of police officers, soldiers, or vehicles that is put around an area to stop people going there
cordon of
A cordon of police surrounded the building.
cordon around
the security cordon around the capital
II. cordon 2 BrE AmE verb
cordon something ↔ off phrasal verb
to surround and protect an area with police officers, soldiers, or vehicles:
Police cordoned off the street where the murder took place.