thermal
UK: ˈθɜːməl | US: ˈθɜːrməl
adj. relating to heat or temperature
n. a rising current of warm air
n. (often plural) thermal clothing designed to retain body heat
The word "thermal" derives from the Greek root therm- (θερμός), meaning "heat," combined with the Latin-derived suffix -al, which forms adjectives. The Greek therm- appears in many scientific terms (e.g., thermometer, thermodynamics), reflecting its foundational role in describing heat-related phenomena. The suffix -al was adopted via Old French from Latin -alis, standardizing the adjective form in English. Over time, "thermal" expanded from purely scientific contexts (e.g., thermal energy) to everyday uses (e.g., thermal underwear).
The thermal springs in Iceland attract tourists year-round.
Birds use thermal currents to glide effortlessly in the sky.
Wear thermal layers to stay warm during winter hikes.
The engineer studied the thermal conductivity of the new material.
Thermal imaging cameras detect heat signatures in complete darkness.