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

Results forwebdisk.moonlightsoundtrack.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2017-12-04T21:39:25.43	2017-12-03T00:00:00	2018-03-03T23:59:59	moonlightsoundtrack.com	webdisk.moonlightsoundtrack.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-09-19T20:29:20.471	2017-09-18T00:00:00	2017-12-17T23:59:59	moonlightsoundtrack.com	webdisk.moonlightsoundtrack.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-07-05T20:28:26.199	2017-07-04T00:00:00	2017-10-02T23:59:59	moonlightsoundtrack.com	webdisk.moonlightsoundtrack.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-04-21T20:17:43.517	2017-04-19T00:00:00	2017-07-18T23:59:59	moonlightsoundtrack.com	webdisk.moonlightsoundtrack.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"