[ kuhn-vek-shuhn ]
/ kənˈvɛk ʃən /
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Physics. the transfer of heat by the circulation or movement of the heated parts of a liquid or gas.
Meteorology. the vertical transport of atmospheric properties, especially upward (distinguished from advection).
the act of conveying or transmitting.
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Origin of convection

1615–25; <Late Latin convectiōn- (stem of convectiō) a bringing together. See convect, -ion


con·vec·tion·al, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What is convection?

Convection is the transfer of heat by the movement of heated parts of liquids and gases. Convection happens in liquids and gases because, unlike in a solid, molecules are able to freely move.

For example, the air molecules in your living room continually move around, all moving at about the same speed. However, if you turn on an electric heater, the air particles close to the heater will get hotter, which means they will have more energy and will move faster. Faster-moving particles are less dense, or lighter, and will flow to the top of the living room. Colder particles are denser and will move down toward the floor when the hot particles move up. This movement of hot air is convection.

The cold particles that move toward the floor will now be close to the heater. They, too, will heat up and move faster. And just like the earlier particles, these particles will move up, pushing colder particles down. This cycle is called a convection current or a convection cycle. The cycle will continue until an outside force changes things, such as turning off the heater.

Why is convection important?

The first records of the term convection come from around 1615. It ultimately comes from the Latin word convectiō, meaning “a bringing together.” In convection, hot particles “gather together” at a high altitude or elevation.

Convection happens every day in nature. For instance, thunderstorms are formed through a convection cycle. Warm, moist air rises, while cooler air falls. Once it rises, it cools and the moisture in the air becomes water vapor. As the cycle continues, the water vapor will form a cloud. When a lot of water vapor forms, like during a humid day in the summer, a thunderstorm cloud can form. At some point, all that water vapor in the cloud will fall to the ground in the form of rain. The storm will continue as long as hot water vapor continues to feed the cycle.

Convection is also the reason we arrange heating and cooling equipment the way we do. Usually, air conditioners and cooling vents are placed high on the ceiling so that the cold air will fall toward the ground and cool you. Similarly, heaters and heating vents are placed low on the floor so that the hot air will rise up and heat your body as it does so.

Did you know … ?

Hail is also a product of convection. In fact, a hailstone has layers like a tree that you can count to see how many times it went through the convection cycle before it became too heavy and fell to the ground.

What are real-life examples of convection?

Convection is a common process that is responsible for weather patterns and wind movement.


What other words are related to convection?

Quiz yourself!

True or False?

Convection occurs when hot particles move upward and cold particles move downward to replace them.

How to use convection in a sentence

British Dictionary definitions for convection

/ (kənˈvɛkʃən) /

a process of heat transfer through a gas or liquid by bulk motion of hotter material into a cooler regionCompare conduction (def. 1)
meteorol the process by which masses of relatively warm air are raised into the atmosphere, often cooling and forming clouds, with compensatory downward movements of cooler air
geology the slow circulation of subcrustal material, thought to be the mechanism by which tectonic plates are moved

Derived forms of convection

convectional, adjectiveconvective, adjective

Word Origin for convection

C19: from Late Latin convectiō a bringing together, from Latin convehere to bring together, gather, from vehere to bear, carry
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for convection

[ kən-vĕkshən ]

Heat transfer in a gas or liquid by the circulation of currents from one region to another.
Fluid motion caused by an external force such as gravity.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for convection

[ kən-vĕkshən ]

Current in a fluid caused by uneven distribution of heat. For example, air on a part of the Earth's surface warmed by strong sunlight will be heated by contact with the ground and will expand and flow upward, creating a region of low pressure below it; cooler surrounding air will then flow in to this low pressure region. The air thus circulates by convection, creating winds. See Note at conduction.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for convection


The motion of warm material that rises, cools off, and sinks again, producing a continuous circulation of material and transfer of heat. Some examples of processes involving convection are boiling water, in which heat is transferred from the stove to the air; the circulation of the atmosphere of the Earth, transferring heat from the equator to the North Pole and South Pole; and plate tectonics, in which heat is transferred from the interior of the Earth to its surface.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.