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

Results forwebdisk.buybitumen.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2017-11-27T18:29:28.931	2017-11-25T00:00:00	2018-02-23T23:59:59	buybitumen.com	webdisk.buybitumen.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-09-13T18:14:49.618	2017-09-10T00:00:00	2017-12-09T23:59:59	buybitumen.com	webdisk.buybitumen.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-06-29T18:09:55.622	2017-06-26T00:00:00	2017-09-24T23:59:59	buybitumen.com	webdisk.buybitumen.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"