The term 'sub-ca' seems to be coined and used mostly/only by easyrsa. More commonly, this type of certificate is called an intermediate CA [0]. The term sub-ca, while logical is actually a Microsoft CA term [1]. The command itself remains the same for now, as it is shorter/easier to type. [0] https://en.wikipedia.org/w/index.php?title=Intermediate_certificate_authorities [1] https://en.wikipedia.org/wiki/Public_key_infrastructure Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>