What does boiling mean?
Boiling is most familiar as the process by which a liquid — usually water — is heated to the point where it bubbles vigorously and turns into vapour. In everyday English it also works as a vivid informal adjective for extreme heat, whether of weather, objects, or tempers, as in 'a boiling day' or 'she was boiling with rage'. Figuratively, boiling conveys intensity on the verge of eruption: emotions described as boiling are agitated and ready to overflow, much like a pot left too long on the stove. The word belongs to an old European vocabulary of bubbling and swelling, sharing distant roots with terms such as 'ebullient', which literally once meant 'boiling out'. Practical, sensory, and expressive all at once, boiling is one of those rare words equally at home in a recipe, a weather report, and a description of anger.
Heating a liquid until it bubbles rapidly and converts to vapour, or doing so oneself as a liquid.
"The kettle had been boiling for a minute before she noticed."
Used both transitively ('boiling vegetables') and intransitively ('the water is boiling').
Informal: extremely hot.
"It was absolutely boiling in the crowded train carriage."
Chiefly British and Australian colloquial use; often strengthened to 'boiling hot'.
The action or process of boiling a liquid.
"Ten minutes of gentle boiling reduced the sauce perfectly."
Mostly found in technical, scientific, and culinary contexts.
At sea level, water always boils at exactly 100 °C — but climb a mountain, and lower air pressure can bring that point down by more than ten degrees, which is why tea tastes weak on high peaks.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of boiling
Boiling derives from the verb boil, which entered Middle English from Old French 'boillir', itself descended from Latin 'bullīre', meaning 'to bubble or boil', formed on 'bulla', the Latin word for a bubble. The same Latin root gives us 'ebullient' and 'ebullition', both originally describing liquid bubbling forth. English has used the word since the medieval period, and its extended senses — seething anger, scorching heat — developed naturally from the image of violently bubbling liquid.
Related word forms
How boiling is actually used
As an adjective, 'boiling' is informal and typically intensified ('boiling hot'); British speakers often say 'it's boiling' as a standalone remark about the weather. In figurative use ('tempers were boiling'), it suggests suppressed anger close to erupting. The noun sense usually appears in technical or culinary writing rather than everyday speech.
Easily confused with boiling
Broiling means cooking by direct intense heat from above (or grilling), while boiling means cooking in liquid heated to its bubbling point.