Hi Barb and welcome to the project meditation community.
As Hazel says, a "thread" is a topic of discussion and is made up of "posts" (the initial post is the thread starter, and the rest are replies to it)
I see you've got your email address as your username. That may not be a good idea as it could lead to you getting more spam in your email account. It may be a good idea to contact the site administrators (using the "Contact Us" link at the bottom of the page (or use this link
Project-Meditation - Powered by Kayako SupportSuite Help Desk Software ) and ask them to change your username to something more friendly and less revealing.
Hugs
Giles