The term 'sunbelt' is a modern American English compound, formed in the mid-20th century by directly combining two native English words. 'Sun', with its Proto-Germanic root sunnon, refers to the source of light and warmth. 'Belt', from Latin balteus via Germanic, metaphorically extends from an article of clothing to describe a distinct geographical band or region. The compound logically names a specific climatic zone by its defining feature—consistent sunshine—and exemplifies how common Anglo-Saxon roots are repurposed to create precise socio-geographic terminology.

Structure: sun (star) + belt (zone) - sun: From Old English sunne, of Germanic origin; related to Dutch zon and German Sonne. Functions as the core noun denoting the celestial body. - belt: From Old English belt, of Germanic origin; from Latin balteus 'girdle'. Functions as a noun meaning a broad, continuous strip or zone.