What is the meaning of Breve?

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.

Source: Webster’s Revised Unabridged Dictionary (1913), via OPTED