Cordon and search is a military tactic to cordon off an area and search the premises for weapon

Weapon

A weapon, arm, or armament is a tool or instrument used with the aim of causing damage or harm to living beings or artificial structures or systems...

s or insurgent

Insurgent

Insurgent, insurgents or insurgency can refer to:* The act of insurgency-Specific insurgencies:* Iraqi insurgency, uprising in Iraq* Insurgency in Jammu and Kashmir, uprising in India* Insurgency in North-East India...

s. It is one of the basic counter insurgency

Counter insurgency

A counter-insurgency or counterinsurgency involves actions taken by the recognized government of a nation to contain or quell an insurgency taken up against it...

 operation. Other related operations are Cordon and knock and Cordon and kick.

Cordon and knock is a relatively new technique in military operation

Military operation

Military operation is the coordinated military actions of a state in response to a developing situation. These actions are designed as a military plan to resolve the situation in the state's favor. Operations may be of combat or non-combat types, and are referred to by a code name for the purpose...

s. It has taken over the old term of a simple house search. It is part of new doctrine called Stability and Support Operations

Stability and support operations

Stability and support operations is a US military term for operations involve military forces providing safety and support to friendly noncombatants while suppressing threatening forces....

or SASO. It is a technique used where there is no hard intelligence of weapons in the house and therefore is less intense than a normal house search. It is used in urban neighborhoods. The purpose of the mission is to search a house with as little inconvenience to the resident family as possible.