Or else. Used as a direction to the performer to designate an alternate section or passage.
Origin of ossiaItalian, from o sia, or let it be : o, or (from Latin aut) + sia, third person sing. present subjunctive of essere, to be (from Latin esse; see es- in Indo-European roots).
- (music) In a musical score an ossia is an alternative version of the music, often just a few measures long.