(1) (music) an electronic simulation of a pipe organ
(2) A free-reed instrument in which air is forced through the reeds by bellows
(3) Wind instrument whose sound is produced by means of pipes arranged in sets supplied with air from a bellows and controlled from a large complex musical keyboard
(4) A fully differentiated structural and functional unit in an animal that is specialized for some particular function
(5) A periodical that is published by a special interest group
"The organ of the communist party"
(6) A government agency or instrument devoted to the performance of some specific function
"The Census Bureau is an organ of the Commerce Department"