Sheet Music
Sheet Music Symbols & Indicators
Besides the key signature, time signature, and notes there can be a lot more symbols and instruction notation on the pages. The following are the definition of many things you might encounter and how to interpret what they mean.
Bar Lines
Bar lines are used to separate measures.

Double Bar Lines
These indicate some change in the music, such as a new musical section, or a new key/time signature.

Single Simile Mark
Repeat the previous measure. Used often in notation for things like drums, where the pattern is the same for many measures.

Double Simile Mark
Repeat the previous two measures. Used often when a repeated phrase is two measures instead of one. Often seen with drum notation with a two-measure drum pattern.

Segno Symbol
Litterally, translates to the "Sign". The segno mark used with the dal segno instruction. The segno is used to mark a point in the music to jump to at some point. A music piece can contain more than one segno marker.

Coda Symbol
Indicates a forward jump in the music to its coda, which may be marked with the same sign or can be written litteraly.

Volta Brackets
Volta brackets (1st and 2nd endings, or 1st- and 2nd-time bars) A repeated passage is to be played with different endings on different playings. Although two endings are most common, it is possible to have multiple endings (1st, 2nd, 3rd ...).

Da Capo
literally, "From Top" Tells the performer to repeat playing of the music from its beginning. This is usually followed by al fine (lit. "to the end"), which means to repeat to the word fine and stop, or al coda (lit. "to the tail"), which means repeat up to the coda sign and then jump forward into the coda.

Dal Segno
Literally, "From the sign" Tells the performer to repeat playing of the music starting at the nearest preceding segno. This is followed by al fine or al coda just as with da capo.

Coda
In music, a coda, Italian for "tail" is a passage that brings a piece (or a movement) to an end. It may be as simple as a few measures, or as complex as an entire section.

Sheet Music Navigation Example
The following piece of music uses many of the described tools for navigating

The performer plays measures 1-4, three times in succession, then plays measure 1-2-3-5. Following they play measures 6-9, then back to the segno sign at measure 6, then they play measures 6-7, then jump to the Coda section at the Coda sign.
The entire sequence:
1-2-3-4
1-2-3-4
1-2-3-4
1-2-3-5
6-7-8-9
6-7-10