These five lines are called the staff or stave.
Music notes are written in the spaces and on the lines of the staff.
This symbol is called a treble clef.
A staff with a treble clef written on it is called a treble staff.
This symbol is called a bass clef.
A staff with a bass clef written on it is called a bass staff.
High notes are written on the treble staff, and are usually played with your right hand.
Low notes are written on the bass staff, and are usually played with your left hand.
When the treble and bass staves are joined together by a line and a bracket, they are called a grand staff. Piano music is written on the grand staff.
Music is divided into bars (sometimes called measures) by bar lines. In this example there are two bars of music.