Rest (music)
A rest is an interval of silence in a piece of music, marked by a symbol indicating the length of the pause. Each rest symbol corresponds with a particular note value:
The quarter (crotchet) rest 
may also be found as a form 
in older music.
(The four-measure rest or longa rest is a symbol found in Western musical notation denoting a silence four times the duration of a whole rest. They are only used in long silent passages which are not divided into bars.
The two-measure rest or breve rest is another symbol found in Western musical notation denoting a silence twice the duration of a whole rest.
The combination of rests used to mark a pause follows the same rules as for notes. For more details see note value.
One-bar rests
When an entire bar is devoid of notes, a whole (semibreve) rest is used, regardless of the actual time signature. The only exceptions are for a 4/2 time signature (four half notes per bar), when a double whole rest is typically used for a bar's rest, and for time signatures shorter than 3/16, when a rest of the actual measure length would be used. For a 4/2 bar rest, it is also common to use the whole rest instead of the double whole rest, so that a whole-bar rest for all time signatures starting from 3/16 is notated using a whole note rest. Some published (usually earlier) music places the numeral "1" above the rest to confirm the extent of the rest.
