monitors/speakers?

Monitors are speakers. There are two main types of speakers: floorstanders, which physically stand on the floor; and monitors which are smaller and sit on stands. Floorstanders generally have more bass because they are bigger and have dedicated woofers.

Arthur

Monitors are used in the music industry both in live events and also in studios (recording/mixing/mastering). In general, this equipment must handle large dynamic range with a high degree of fidelity (more stringent requirements than for home use).

The term is used by many domestic/consumer speaker manufacturers to give the impression that they produce professional audio quality products. Some do and some don't - so you can't really tell from the moniker.

Both terms, monitor and reference, have no meaning as applied to consumer speakers. Calling stand mounted speakers monitors is market-speak.