What is a host only cookie?

Question

I would like to know what is a host only cookie.

While retrieving a form auth, browser gets in the headers a JSESSIONID cookie shown as

Answer 1

Host Only cookie means that the cookie should be handled by the browser to the server only to the same host/server that firstly sent it to the browser.

You don't want to send this host only cookie for ad campaigns, as it might contain sensitive information.