SAML, OAuth and OpenID Connect are standards that let people sign in or grant permissions between applications without sharing passwords. SAML and OpenID Connect are used for single sign-on (SSO), and OAuth to authorize one application to access your data in another, like when you connect a calendar to your email.
Related term in this glossary: IAM (identity and access management)
SAML, OAuth 2.0, OpenID Connect, OIDC, SSO, identity federation