No, they don't. A master/slave configuration (of hard drives, for example) involves two things. I specifically included it to head off the exact objection you're raising.

"...the slash is now used to represent division and fractions, as a date separator, in between multiple alternative or related terms"

-Wikipedia

And what is a key/value store? A store of related terms.

And if you had a system that only allowed a finite collection of key values, where might you put them? A key-value store.

The hard drives are either master or slave. A hard drive is not a master-and-slave.