thin

Thin is an adjective that describes objects or bodies with a small distance between opposing surfaces, or a light or slender build in living beings. It can refer to physical thickness, such as a thin sheet, a thin layer, or a thin slice. It can also describe people or animals that are slender or lean, sometimes implying little body fat or musculature. The word is often contrasted with thick and fat, but in many cases context clarifies whether thickness, width, or mass is meant.

Thin is also used metaphorically to express scarcity, fragility, or insubstantiality, as in thin ice, thin margins, or thin air. Idioms can convey risk, slight likelihood, or weak support.

In science and technology, thin appears in terms such as thin film, a layer with thickness ranging from nanometers to micrometers, used in optics, electronics, and coatings, and in computing as a thin client, a lightweight device that relies on a server for most processing.

Etymology: Thin originates from Old English thynne, thinne, from Proto-Germanic roots related to Dutch dun and German dünn, and is cognate with those terms in other Germanic languages.