An instrumental is not the same thing as a karaoke but unfortunately many releases show karaoke called as instrumental.
Karaoke is the same recording except that they have removed the vocal track from the mix. This is why it is a recording to recording relationship, it is like a remix. Only the accompaniment (backing tracks) remain. No more melody.
An instrumental has the melody part played by instrument. Here you will link to the work as instrumental, which also means that the lyrics of the work are not rendered in the recording.