Balungan

The balungan () is sometimes called the "core melody" or, "skeletal melodic outline," of a Javanese gamelan composition. This corresponds to the view that gamelan music is heterophonic: the "balungan" is then the melody which is being elaborated. "An abstraction of the inner melody felt by musicians," the "balungan" is, "the part most frequently notated by Javanese musicians, and the only one likely to be used in performance."
The group of instruments which play the closest to the "balungan" are sometimes also called the "balungan", or "balungan" instruments. These are the "saron" family and the "slenthem". In many pieces, they play the "balungan". However, they can also elaborate on the parts in a variety of techniques. It is possible that there is no instrument playing the "balungan", although many musicians claim that the "balungan" is still present.
The term has been a source of some controversy, as various writers may define it differently. Sometimes it is identified with the melody played on the "saron" (whose range is limited to an octave), but sometimes it is identified with a wider tessitura that is implied by the patterns on other instruments. This multi-octave melody is the one given in kepatihan notation, the cipher notation used for gamelan pieces. 
Lagu is a related term, which is used by Sumarsam and is sometimes translated as "inner melody." It can mean the multi-octave "balungan", or a more implicit melody. There is no consensus on the use of either term, and they may be used differently by different writers or in different contexts.
Other uses.
Balungan is also the name of a tiger. It is also the name of a journal published by the American Gamelan Institute.
Definitions.
Sumarsam argues that the use of the term, beginning directly after the introduction of notation, arose from the use of notation, theory, and pedagogy.