When I was younger (and not really analyzing language—because, really, what kid sits around and analyzes language?), I used to think that chord and cord were just different ways to spell the same thing.
Chord: three or more musical tones played simultaneously
Cord: a long, flexible, woven strand; an insulated electrical cable used to connect an appliance with a receptacle
How to Remember
Your computer uses a cord. But you play a chord on your cello, which borrowed chord's h sound, since it already has three or more musical ones.