Software Supply Chain
Certificate Authority
Also: CA
An organisation trusted to vouch that a public key belongs to a given website, by signing a certificate for it.
In more detail
Your device ships with a list of certificate authorities it trusts. If a CA signs a certificate for a name, the device accepts it. That makes every trusted CA a single point of failure: anyone who holds a CA's signing key can create a certificate that browsers and programs accept for any site.