Demo
来自Big Physics
early 20th century: abbreviation of demonstration and demonstrate.
wiktionary
Clipping of demonstration and various other words beginning with "demo-".
Clipping of demonstrate.
Clipping of demolish.
etymonline
demo (n.)
"music recording given out for promotional purposes," by 1958 in Billboard magazine headlines and advertisements, short for demonstrationdisk. The word was used earlier to mean "a public political demonstration" (1936).
