What does friction mean?
Friction is the force that resists motion when two surfaces slide or press against each other. It explains why shoes grip pavement, why brakes stop a car, and why rubbing your hands produces warmth — while also being the enemy of efficiency in engines and machinery, where engineers work to reduce it with lubricants, bearings, and polished surfaces. Physicists measure it through the coefficient of friction, a number expressing how strongly two particular materials resist sliding past one another. Beyond physics, friction has an important figurative life: it names the tension, irritation, or open discord that arises between people, colleagues, or nations, as in 'trade friction' or 'family friction'. This dual character makes the word especially useful — it bridges the laboratory and everyday conversation, letting speakers describe both a measurable force and a human mood with a single, vivid term borrowed from the same ancient idea of rubbing.
The resistance that one surface or object encounters when moving over or against another.
"Tires rely on friction to keep the car on the road."
Disagreement, tension, or conflict between people or groups.
"Budget cuts caused friction within the committee."
Friction is usually uncountable. A plural form appears occasionally in economics and social science ('trade frictions', 'labor-market frictions') to denote multiple instances or kinds of friction.
"Economists studied the frictions that keep workers from matching quickly with jobs."
Without friction you could not walk, write, or even hold this phone — every grip you take for granted is friction at work.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of friction
Friction comes from the Latin verb fricare, meaning 'to rub', via its past-participle stem frict-. English adopted it in the early seventeenth century, initially in scientific writing about rubbing and grinding. The same Latin root lies behind related words such as fricative, the class of consonants produced by friction of breath through a narrow opening, and reaches French in fricassée, a dish named for its frying and stirring. Its figurative use for interpersonal tension developed later from the physical metaphor of surfaces grinding against each other.
How friction is actually used
In physics and engineering contexts, friction carries no emotional charge and is often treated as a quantity to be measured or minimised. In everyday social use, it implies disagreement or awkwardness and tends toward a mildly negative connotation. The figurative sense of interpersonal friction is common in workplace and political discourse.
Easily confused with friction
Friction is the noun naming the resistance itself, while frictional is the adjective describing things relating to it (as in 'frictional force').