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

Results forstaging.teacher.captaincoder.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2020-10-02T11:57:28.719	2020-10-01T00:03:33	2020-12-30T00:03:33	www.idealschape.com	staging.teacher.captaincoder.com	C=US, O=Google Trust Services, CN=GTS CA 1D2
2020-10-01T01:03:33.649	2020-10-01T00:03:33	2020-12-30T00:03:33	www.idealschape.com	staging.teacher.captaincoder.com	C=US, O=Google Trust Services, CN=GTS CA 1D2
2020-09-30T20:23:37.568	2020-09-30T19:23:37	2020-12-29T19:23:37	staging.teacher.captaincoder.com	staging.teacher.captaincoder.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-09-30T20:23:37.381	2020-09-30T19:23:37	2020-12-29T19:23:37	staging.teacher.captaincoder.com	staging.teacher.captaincoder.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3