Question

What is the name of the thin piece of glass used in preparing a slide?
Thank you in Advance!

Answer 1

They were called cover glasses in my day.

Answer 2

I guess they still call it that.
http://www.google.com/search?q=define%3A+cover+glass&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a