Friction
Etymology
From Latin "fricare" (to rub). The literal rubbing sense broadened into a common metaphor for any interpersonal or systemic resistance — “friction in the deal.”
noun · /FRIK-shun/
The resistance that arises when two surfaces slide or try to slide against each other.
What it names
The reason motion runs down without constant effort, and by metaphor the drag that any smooth process meets in the real world.
Example
Friction between the brake pads and the wheel converts the car’s motion into heat.
Related idea
Friction opposes motion between surfaces in contact; viscosity is the internal friction within a flowing fluid. One slows a sliding book, the other slows honey pouring from a jar.
noun · /FRIK-shun/
Conflict, tension, or ongoing disagreement between people or groups.
What it names
It borrows the physics image of resistance for human relations — the everyday grinding that slows cooperation and wears people down.
Example
There was constant friction between the two departments over the shrinking budget.
Related idea
The opposite of rapport, where minds mesh smoothly — friction is the everyday grinding of small disagreements that slows cooperation and wears people down.
noun · /FRIK-shun/
Anything that makes a process slower, harder, or more effortful for the people going through it.
What it names
The invisible drag in a workflow or transaction — extra clicks, forms, or steps — so designers can talk about removing it (‘frictionless’).
Example
Adding a required sign-up step introduced friction that cut checkout completions in half.
Related idea
Unlike the interpersonal sense (conflict between people), this friction is impersonal — resistance built into a system, much closer to the physical drag the word starts from.