drag
drag
/dræɡ/
The longitudinal retarding force exerted by air or other fluid surrounding a moving object.
In fluid dynamics, drag is the resistance force acting opposite to the relative motion of any object moving with respect to a surrounding fluid.
The story behind the word. Coming from Germanic roots meaning 'to pull' or 'to draw', the word originally described pulling a heavy sled or cart. In physics, it was adopted to describe how a fluid 'pulls back' on a moving object, slowing it down.
Word relationships
- resistance: Resistance is a broad term for any opposing force, while drag is specifically the fluid dynamic resistance opposing motion.
- friction: Friction occurs between solid surfaces sliding past each other, whereas drag is the resistance of a fluid medium.
- thrust: Thrust is the forward force that propels an object, directly opposing the backward pull of drag.
Commonly confused with
- gravity: Gravity pulls an object downward toward the earth, while drag resists an object's motion through a fluid in the opposite direction of travel.
Word family
- drag (verb): To pull along forcefully; to experience resistance while moving.
Collocations
- aerodynamic drag
- reduce drag
- drag coefficient
- viscous drag
Example sentences
- "By smoothing out the car's rear profile, designers managed to reduce aerodynamic drag and improve fuel efficiency." Automotive design
- "Swimmers wear specialized, tight-fitting caps and suits to minimize drag as they glide through the water." Competitive sports
Memory hook
Think of a heavy parachute 'dragging' behind a runner, pulling them backward. Drag = Dragging a parachute behind you.
When not to use
Do not confuse with the colloquial verb 'to drag' (pulling something along the ground), though they share an origin.
Fun facts
- Cyclists ride in tight packs (drafting) because the lead rider takes the brunt of the air drag, allowing those behind to save up to 40% of their energy.
Explore more words
aerodynamic, hydrodynamic, aerodynamics, thrust, drafting, downforce
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