What is "slendro"

Slendro (called salendro by the Sundanese) is a pentatonic scale, the older of the two most common scales (laras) used in Indonesian gamelan music, the other being pélog. In Javanese the term is said to derive either from " Sailendra", the name of the ruling family in the eighth and ninth centuries when Borobudur was built, or from its earlier being given by the god Sang Hyang Hendra.