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

Results forwebdisk.gigapace.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-12-29T23:54:15.894	2019-12-29T22:54:15	2020-03-28T22:54:15	gigapace.com	webdisk.gigapace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-12-29T23:54:15.697	2019-12-29T22:54:15	2020-03-28T22:54:15	gigapace.com	webdisk.gigapace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-10-29T21:15:50.85	2019-10-29T20:15:50	2020-01-27T20:15:50	gigapace.com	webdisk.gigapace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-10-29T21:15:50.709	2019-10-29T20:15:50	2020-01-27T20:15:50	gigapace.com	webdisk.gigapace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-08-29T13:48:33.228	2019-08-29T12:48:32	2019-11-27T12:48:32	webmail.gigapace.com	webdisk.gigapace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-08-29T13:48:32.663	2019-08-29T12:48:32	2019-11-27T12:48:32	webmail.gigapace.com	webdisk.gigapace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3