Plain-English AI definitions for legal professionals. For what bars actually require, see the Legal AI Compliance Register.

Open model

Using AI Last reviewed 2026-06-11

Definition An AI model whose weights are published for anyone to download, run, and modify—on their own hardware if they choose. Contrasts with closed models accessible only through a provider's service.

In more depth

Open models—often called open-weight models, since training data and code may stay private—allow organizations to run AI entirely inside their own infrastructure, keeping data on premises. That control comes with responsibility: the hosting organization must secure, update, and evaluate the model itself. Licenses vary, with some permitting unrestricted commercial use and others carrying conditions, so open does not mean license review can be skipped.

Related terms

About the editor: MHSB Solutions, Research desk. MHSB Solutions is not a law firm. This glossary is educational information, not legal advice.

Educational information, not legal advice. AI terminology and tools change quickly; definitions reflect usage as of the last-updated date. For what bar associations and courts actually require of lawyers using AI, see legalaicompliance.help and consult a licensed attorney in your jurisdiction.