Sea (or wind) waves are generated by the local prevailing wind and vary in size according to the length of time a particular wind has been blowing, the fetch (distance the wind has blown over the sea) and the water depth.

Swell waves are the regular longer period waves generated by distant weather systems - think of a rock thrown in a pond, and you'll see swells.

Sea state describes the combination of sea (wind) waves and swell.

Waves & Swell are often used to mean the same thing .. in common language many like to think of "swell" as the regularly spaced lumps that approach your local surf spot, and "waves" as when they break/something to stick your surfboard on.

Wave height (trough to crest) refers the average height of the highest one-third of the waves.