Prefix · heat / temperature
From Greek "thermē" (heat): one of science's most useful roots, appearing in physics, medicine, and everyday technology.
Written by Bryan López, English teacher · Updated
"Therm-" / "thermo-" comes from Greek "thermē," meaning heat. It is one of the most productive scientific roots in English, appearing in thermometers, thermodynamics, hypothermia, and even the brand name "Thermos" (the insulated container that maintains temperature).
Spanish uses "termo-": termómetro (thermometer), termodinámica (thermodynamics), termostato (thermostat), hipotermia (hypothermia). The root is so productive that it appears across physics, medicine, earth science, and household products in both languages.
Therm- / thermo- combines with other roots to describe heat, temperature, and thermal energy:
"Exothermic" describes a chemical reaction that releases heat (exo- = outside); "endothermic" describes one that absorbs heat (endo- = within). These are essential terms in chemistry and biology.
therm-/θɜːrm/
Tap the button to hear how the prefix sounds. Each word in the table has its own audio.
"Thermal underwear" retains body heat in cold weather — the word relates to temperature regulation, not just warmth. "Hypothermia" is also built on this root, describing dangerously low temperature.
A trick to remember it
Therm- = heat/temperature. The thermometer measures it, the thermostat regulates it, thermodynamics studies how it flows. Add "hypo-" (below) for hypothermia and "hyper-" (above) for hyperthermia. This root appears in physics, medicine, geology, and everyday kitchen gadgets.
Exercise 1 · Form the word
Exercise 2 · Pick the right one
When a person's core body temperature drops dangerously low due to cold exposure, the condition is called ___.
The prefix therm- from Greek "thermē" (heat): one of science's most useful roots, appearing in physics, medicine, and everyday technology. In Spanish it usually maps to termo-.
The prefix therm- is pronounced /θɜːrm/. For example, "thermometer".
"ometer" becomes "thermometer". It is a typical example of the therm- prefix.
un-, re-, pre-, dis-, over-, in-... every beginning you need to unlock thousands of English words at once.