Finnish to English Other General / Conversation / Greetings / Letters

Hello,

Is anyone familiar with the term "päälilehti", as used in a context like "tulosteen päälilehti"?

I've seen the translation "cover sheet" proposed, which makes some sense contextually -- however, the source of this proposal didn't seem completely reliable to me.

Also, the form "pääli-" (as opposed to e.g. "päälle") is unfamiliar to me, and makes me think this might be a misspelling.

Thanks for any assistance