1660s, "round, approximately flat surface," from Latin discus "quoit, discus, disk," from Greek diskos "disk, quoit, platter," related to dikein "to throw" (see discus).
The American English preferred spelling; also see disc. From 1803 as "thin, circular plate;" sense of "phonograph disk" is by 1888; computing sense is from 1947. Disk jockey first recorded 1941; dee-jay is from 1955; DJ is by 1961; video version veejay is from 1982. Disk-drive is from 1952.
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Definitions of DJ from WordNet
comment on music to be played;
Synonyms: disk-jockey / disc-jockey
a person who announces and plays popular recorded music;