Blocking

Blocking is a term used in several domains to denote either the planning and restriction of movement or the act of preventing passage or access. In performing arts, computing, sports, psychology, and information security, blocking shapes how actions unfold and what is visible or permissible.

In theatre and film, blocking is the deliberate placement and movement of actors on a stage or set. Directors use blocking to ensure visibility, establish relationships, and coordinate timing with lighting, scenery, and dialogue. Blocking is typically refined during rehearsals and noted in scripts or staging plans.

In sports, blocking refers to using the body to impede an opponent or to protect a teammate. The legality and form of blocking vary by sport: some blocks are legal plays, others are fouls. Blocking can also describe defensive actions intended to prevent a shot or pass, or offensive linemen maintaining blocks during plays.

In computing, blocking describes a state in which a process or thread waits for an operation to complete, preventing progress. Blocking I/O suspends the caller until data is available. Blocking also appears in data structures and synchronization, such as block devices or blocking queues used to coordinate access to resources.

In psychology, the blocking effect is a learning phenomenon in classical conditioning where prior learning about one stimulus reduces or prevents learning about a new stimulus when the two are paired together.

In information security and everyday technology, blocking means denying access or admission. Firewalls block unauthorized network traffic, while content blockers prevent certain websites or materials from loading on devices or within applications.