What's the difference between waves, seas and swell?
Waves are generated by wind moving over water; they indicate the speed of the wind in that area. Swell are waves (usually with smooth tops) that have moved beyond the area where they were generated. The distance between the crests, or tops, of the waves that make up swell is usually much greater than the distance between waves being actively generated by wind blowing over the water. Seas (usually described by the term combined seas) refers to wind waves and swell working together. Waves and seas are described by the height from trough to crest; swell also is described by the direction it's coming from.