a diacritical mark (U-shaped) placed over a vowel to indicate a short sound
source: WordNet 3.0
A note or character of time, equivalent to two semibreves or four minims. When dotted, it is equal to three semibreves. It was formerly of a square figure (as thus: &?; ), but is now made oval, with a line perpendicular to the staff on each of its sides; -- formerly much used for choir service.
