Kotamadya is an obsolete term for governmental unit in Indonesia, equivalent to a town (chartered community). Now people use the term kota (city) to represent the same governmental unit. However a kota in Indonesia isn't simply a city, it is independent of and the same level as Regency (Indonesia), to be distinguished from other communities lie under the jurisdiction of a regency. A kotamadya is led by a walikotamadya. The term "madya" roughly means middle. The word Kota is derived from Sanskrit/Pali word kota meaning 'fort'.
References
Kotamadya Wikipedia(Text) CC BY-SA