access

Access is the opportunity or right to reach, enter, use, or obtain something. It can be physical, informational, or digital, and it is often constrained by security, policy, and design. Physical access refers to the ability to enter a place or use a resource such as buildings, rooms, or equipment, usually controlled by locks, badges, or guards. Access control systems manage who may enter or use a resource, using mechanisms such as authentication, authorization, and auditing. Common models include discretionary access control, role-based access control, and mandatory access control, often implemented with access control lists or capabilities.

In information technology, access governs permissions to files, databases, networks, and services. Users are verified (authentication) and granted rights (authorization). Poorly managed access can lead to data breaches or service outages, whereas overly restrictive access can hamper productivity. Access management covers provisioning, revocation, and auditing of permissions across systems and applications.

In policy terms, access to information laws require governments and organizations to disclose data upon request, subject to exemptions. Access to care refers to the ability to obtain medical or social services, and is a focus of policy and equity discussions. In data and network contexts, access also concerns how users connect to services and whether they can sustain usable, private, and reliable connections.

Accessibility denotes the design of products, services, and environments to be usable by people with a range of abilities. This includes assistive technologies and guidelines such as web content accessibility guidelines (WCAG).

Overall, access involves balancing security, privacy, usability, and equal opportunity across physical, informational, and digital domains.