Definition and background:
A short melodic, rhythmic, or harmonic pattern that is repeated throughout an entire composition or some portion of a composition. obstinate, persistent; i.e., a short musical pattern that is repeated throughout an entire composition or portion of a composition. Indicates a part that repeats the same rhythm or melodic element. the basso ostinato or ostinato bass occurs in the ground bass of baroque arias where a melody is set over a repeated bass pattern. ostinato is used by the Bavarian composer Carl Orff in his instrumental teaching methods, where it may form a basis for improvisation by pupils.
A musical rhythm or phrase that is repeated over and over again.
Italian. A short musical pattern which repeats throughout a given passage. Ostinatos are generally a part of the supporting or accompanying material in a piece of music
For more information on the music term "Ostinato" check out these other resources:
Wikipedia - Glossary of Musical Terminology
Virginia Tech Multimedia Music Dictionary
ORB -- Medieval Music Glossary