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

Results foricmregistry.net

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2016-10-02T01:25:34.477	2011-08-12T00:00:00	2012-08-11T23:59:59	admin.icmregistry.net	admin.icmregistry.net	C=US, O="Thawte, Inc.", CN=Thawte SSL CA
2016-10-02T00:10:29.661	2012-08-08T15:00:37	2013-08-13T00:14:49	ote1.icmregistry.net	ote1.icmregistry.net	C=US, O="Entrust, Inc.", OU=www.entrust.net/rpa is incorporated by reference, OU="(c) 2009 Entrust, Inc.", CN=Entrust Certification Authority - L1C
2016-10-01T14:07:59.996	2011-08-12T00:00:00	2012-08-11T23:59:59	ote1.icmregistry.net	ote1.icmregistry.net	C=US, O="Thawte, Inc.", CN=Thawte SSL CA
2016-09-24T22:22:52.216	2013-08-06T18:10:07	2014-08-14T03:57:28	ote1.icmregistry.net	ote1.icmregistry.net	C=US, O="Entrust, Inc.", OU=www.entrust.net/rpa is incorporated by reference, OU="(c) 2009 Entrust, Inc.", CN=Entrust Certification Authority - L1C
2013-08-19T12:17:51.263	2013-08-06T18:16:24	2014-08-14T03:27:36	admin.icmregistry.net	admin.icmregistry.net	C=US, O="Entrust, Inc.", OU=www.entrust.net/rpa is incorporated by reference, OU="(c) 2009 Entrust, Inc.", CN=Entrust Certification Authority - L1C
2013-04-23T13:05:34.297	2012-08-08T15:02:46	2013-08-13T00:49:01	admin.icmregistry.net	admin.icmregistry.net	C=US, O="Entrust, Inc.", OU=www.entrust.net/rpa is incorporated by reference, OU="(c) 2009 Entrust, Inc.", CN=Entrust Certification Authority - L1C