Čačak (Serbian Cyrillic: Чачак, pronounced [t͡ʃǎːt͡ʃak]) is a city in west-central Serbia. Čačak lies on the Zapadna Morava river, which is the second largest river in Serbia after the Danube (308 km), and between Šumadija and the Dinaric Alps, in the Čačak-Kraljevo valley. It is the administrative center of the Moravica District of Serbia. Čačak is the main economic, cultural and sport center of the district, which includes Gornji Milanovac to the north and Lučani to the southwest. Čačak borders Požega, Serbia (Zlatibor District) to the west, Knić (Šumadija District) to the east and Kraljevo (Raška District) to the southeast. Moravica District includes Čačak, Gornji Milanovac, Lučani and Ivanjica. The lowest altitude is 204 m (confluence of Bresnička reka and Zapadna Morava) and the highest is 985 m (the highest peak of Ovčar mountain). It has 58 settlements. The population of the city itself is 73,331, while the population of the municipality is 115,337. Čačak is 144 km south of the capital city, Belgrade.
Aak Korean pronunciation: [a.ak] is a genre of Korean court music. It is an imported form of the Chinese Yayue.Aak is often labeled as "elegant music" in contrast with other traditional Korean music. Aak began as the music played during the Korean "Jongmyo Shrine's Jerye Ceremony," and was later used for other occasions, and as Korean court music, often with lyrics praising the current ruler.
Aak was brought to Korea in 1116 through a large gift of 428 musical instruments as well as 572 costumes and ritual dance objects from China, a gift to Emperor Yejong of Goryeo from Emperor Huizong of Song. It remained very popular for a time (there were originally no fewer than 456 different melodies in use) before dying out. It was revived in 1430, based on a reconstruction of older melodies.
Aak is one of three types of Korean court music; the other two are dangak and hyangak. Aak is similar to dangak in that both are rarely played and both have Chinese influences.
The article on Aak in the Encyclopaedia Britannica is its very first entry, though it consists only of a cross-reference to the article on gagaku.