What term refers to mature wind-driven waves of one wavelength that form orderly undulations on the ocean surface?

• A. Wind-Wave
• B. Swell
• C. Tidal Wave
• D. Sea Swell

Answer: (B)

Swell refers to mature wind-driven waves that have moved away from their generating winds and organize into a regular, long-train pattern. Once the wind dies or the waves travel far enough, the shorter, choppier aspects fade and the remaining waves form a single dominant wavelength with evenly spaced crests. This happens because longer wavelengths travel faster in deep water, so the wave field becomes smoother and more uniform as it propagates. In contrast, wind-driven seas near the source are typically rough and irregular, while tidal waves relate to tides rather than wind energy. That orderly, long, traveling wave pattern is the hallmark of swell.