5/4 time means that there are five
quarter beats in a
bar. This is not a regular
time signature, and is usually more taxing on the ear than more usual time signatures (such as 4/4, 3/4 and 6/8).
The most famous example of a song in 5/4 time is
Take Five by
Paul Desmond, taken from the
Time Out album by
The Dave Brubeck Quartet.