n.
  - a military operation in which enemy forces surround a town or building, cutting off essential supplies, with the aim of compelling the surrender of those inside.
- a similar operation by a police team to compel the surrender of an armed person.
Phrase
  
    - lay siege to
 conduct a siege of.
- under siege
 undergoing a siege.
 
  Etymology
  ME: from OFr. sege, from asegier ‘besiege’.