Japanese combined kara, empty, with oke, a clipping of okesutora. That longer word had been borrowed from English orchestra. English then took the new Japanese compound back, completing a small linguistic round trip.
Oke is an abbreviation of a loanword, not an ancient Japanese root. Components can have their own borrowing histories.
Sources
- Merriam-Webster · karaoke
Dictionary word history; the component and historical references below supply additional detail.
- Online Etymology Dictionary · karaoke
Historical forms, meanings, and context for the route described here.