Tablature (commonly abbreviated as Tab) is way of notating music that differs from standard notation. Tablature is most commonly used for fretted stringed instruments. It shows a player where to put their fingers whereas standard notation shows what pitches to play. The focus of this article will be guitar Tablature, although the concepts of Tablature apply to all fretted instruments.
The Tablature Staff represents the strings and frets of an instrument. A standard guitar has six strings and therefore guitar Tablature has six lines to a staff.
Each line represents a string, the lowest line is the lowest string (low E) and the highest line is the highest string (high E). From bottom to top the names of the strings are E, A, D, G, B, E.
Numbers on the Staff represent which fret should be pressed by a finger. Tablature is read from left to right and the following example tells you to first put a finger on the second fret of the "A string" and play that note. After that you play an open note (open = no finger down) on the "low E string."
Here is a more complex example:
(Sometimes the stems and beams will be drawn directly on the staff, with circles added around the fret numbers for whole and half notes, creating a hybrid notation system.)
In addition to Tablature I recommend learning Standard Notation as it will greatly help with the learning of music theory.