It can be anything! An apex, subdomain, or even a URL.

Results forwebmail.camptycoon.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2017-09-29T19:09:28.995	2017-09-24T00:00:00	2017-12-23T23:59:59	camptycoon.com	webmail.camptycoon.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-07-22T18:06:59.721	2017-07-10T00:00:00	2017-10-08T23:59:59	camptycoon.com	webmail.camptycoon.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-05-21T18:10:06.115	2017-04-25T00:00:00	2017-07-24T23:59:59	camptycoon.com	webmail.camptycoon.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"