Web, domains and email
CA
Abbreviation for Certification Authority
In short and in plain language
A CA is a body that gives out digital certificates for websites.
It confirms: this coded link belongs to the named domain.
Such bodies set rules with the firms that make browsers. One rule is how long a certificate is good for.
Definition
A CA is a certification authority that issues digital certificates for websites. It confirms that an encrypted connection belongs to the stated domain. In the CA/Browser Forum, these authorities and browser makers jointly set rules, for example on how long TLS certificates remain valid.