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

Results forclayauld.systems

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2016-10-23T16:48:38.463	2016-10-19T11:15:03	2019-10-19T11:15:03	www.clayauld.com	www.clayauld.systems	C=IL, O=StartCom Ltd., OU=StartCom Certification Authority, CN=StartCom Class 1 DV Server CA
2016-10-19T11:48:05.205	2016-10-19T11:15:03	2019-10-19T11:15:03	www.clayauld.com	www.clayauld.systems	C=IL, O=StartCom Ltd., OU=StartCom Certification Authority, CN=StartCom Class 1 DV Server CA
2016-10-19T11:21:19.54	2016-10-19T10:51:54	2019-10-19T10:51:54	clayauld.com	clayauld.systems	C=IL, O=StartCom Ltd., OU=StartCom Certification Authority, CN=StartCom Class 1 DV Server CA
2016-05-25T19:58:53.308	2016-05-25T19:02:09	2017-05-25T19:02:09	clayauld.systems	clayauld.systems	C=IL, O=StartCom Ltd., OU=StartCom Certification Authority, CN=StartCom Class 1 DV Server CA