Relevant: stackoverflow.com/q/38846/1959808

Thanks for suggesting Math.StackExchange as an alternative venue for this question. I agree that this is a relatively basic question about terminology. In this case it so happens that it did arise during research activities.

Thanks! For posterity, Springer's Encyclopedia of Mathematics entry for "strip".

There is no excuse for writing only a prose proof: research.microsoft.com/en-us/um/people/lamport/pubs/proof.pd‌​f