It can be anything! An apex, subdomain, or even a URL.
www.tao.ad.tao.cn.zb.tengine.ingress.alibabacorp.comad.tao.cn.zb.tengine.ingress.alibabacorp.comtao.cn.zb.tengine.ingress.alibabacorp.comcn.zb.tengine.ingress.alibabacorp.comzb.tengine.ingress.alibabacorp.comtengine.ingress.alibabacorp.comingress.alibabacorp.comalibabacorp.comcom