D defs.my
Entry 1 sense Webster, 1913

Semibreve

· Sem·i·breve · IPA /ˈsɛmɪbɹiːv/
01 n. A note of half the time or duration of the breve; -- now usually called a whole note. It is the longest note in general use.
  1. 1.
    A note of half the time or duration of the breve; -- now usually called a whole note. It is the longest note in general use.(Mus.)