swell

Swell is a term with several related meanings across science, everyday language, and medicine. In oceanography, swell refers to a series of long‑wavelength ocean waves that have traveled from their generation region and are no longer directly tied to the local wind. These waves often arrive as smooth, evenly spaced crests and can persist long after the weather that created them has passed. Swell waves can propagate thousands of kilometers with only modest energy loss, and surfers describe conditions using swell period (in seconds) and swell height.

In general use, swell can describe something large, full, or impressive, or be used as a verb meaning to grow in size or volume. For example, crowds can swell, a body of water can swell, or a social event can be described as “swell” in somewhat dated idiom. A related adjective sense can signify high quality or excellence, though this usage is more common in historical or informal speech.

In medicine, to swell refers to the enlargement of tissues due to accumulation of fluid or inflammation, a condition known clinically as edema. Swelling is a common response to injury, infection, or other stimuli and may affect one or more parts of the body.

Overall, swell covers physical wave phenomena, changes in size or quantity, and a range of idiomatic expressions, with usage varying by context and formality.