Glossary

ACME: Automated Certificate Management Environment

A protocol for verifying the ownership of Internet domains and issuing X.509 server certificates. Specified in RFC 8555
API: Application programming interface
ASN.1: Abstract syntax notation one

See https://www.itu.int/en/ITU-T/asn1/Pages/introduction.aspx
CRL: Definition from 5280:

X.509 defines one method of certificate revocation. This method involves each CA periodically issuing a signed data structure called a certificate revocation list (CRL). A CRL is a time-stamped list identifying revoked certificates that is signed by a CA or CRL issuer and made freely available in a public repository. Each revoked certificate is identified in a CRL by its certificate serial number.
IDP: Identity provider

IDP is a term used in the description auf authentication and authorization protocols. The IDP provides information related to a user. The user usually has a way to approve or deny the use of his information.