open

Open is an adjective describing something not closed or blocked, or accessible for use or participation. It can indicate availability to the public, flexibility in process, or lack of restriction. The term is used across domains to denote transparency, accessibility, and inclusivity.

In technology and information, open concepts include open source software, where the source code is publicly available to view, modify, and redistribute; open data, where datasets are licensed for public use; and open standards, which are published and developed through open, collaborative processes to enable interoperability. Open interfaces and APIs also allow integration across systems. Open-source licenses vary in permissions, with permissive and copyleft models.

In publishing and research, open access aims to make scholarly works freely available, while open data and open science emphasize reproducibility and collaborative verification. Open education involves openly licensed learning materials. Licenses such as Creative Commons are commonly used to specify reuse terms.

In governance, open government promotes transparency, citizen participation, and accountability. Open proceedings and records intend to reduce secrecy and increase trust.

As a noun or proper name, The Open refers to The Open Championship, golf's oldest major, often called The Open. The term open can also describe physical actions, such as opening a door or opening a process to external scrutiny.