■ noun
1》 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.
2》 a similar operation by a police team to compel the surrender of an armed person.
Phrases
lay ~ to conduct a ~ of.
under ~ undergoing a ~.
Origin
ME: from OFr. sege , from asegier 'be~'.