Question

What is a bass clef?

Answer 1

A clef placing F below middle C on the 2nd highest line off the staff

Answer 2

There are three kinds of clefs: Treble, Tenor, and Bass Clef.

The Bass Clef is the lowest type of clef. This tells you that the second line from the top is F. So we have F to G to A and on. 

Unlike Treble Clef which tells you that the second line from the bottom is G.

You would have to read more on it to completely understand but I do recommend this site :)

 https://rockhill.instructure.com/courses/328/pages/treble-clef-and-bass-clef