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Equilibrium

ee-kwuh-LIB-ree-um /ˌiːkwɪˈlɪbriəm/

nounB2GRESATUPSC

FormalScientificGeneral

A state in which opposing forces or influences are balanced; a state of physical balance, or a state of balance between opposing forces or influences.

In thermodynamics, equilibrium specifically refers to a state where a system's macroscopic properties (like temperature, pressure, concentration) are constant over time because there are no net changes occurring. It's a state of balance, not necessarily static, but with no net driving forces.

The story behind the word. The word 'equilibrium' comes from the Latin 'aequus,' meaning 'equal,' and 'libra,' meaning 'balance' or 'scale.' Imagine an old-fashioned scale with two pans; when they are 'equally balanced,' you have equilibrium. This concept has been around for centuries, describing a state where opposing forces are perfectly matched, creating a sense of calm and stability.

Word relationships

Balance: A general term for stability; equilibrium implies a specific balance of forces or conditions.
Stability: Refers to resistance to change; equilibrium is the state achieved when forces are balanced, leading to stability.
Stasis: Implies a complete lack of change or movement, which can be part of equilibrium but doesn't capture the dynamic balance.

Imbalance: A lack of balance or equality between opposing forces.
Disequilibrium: A state where forces are not balanced, leading to change.

Word family

equilibriate (verb): to bring into equilibrium
equilibrate (verb): to bring to a state of equilibrium

Collocations

thermal equilibrium
chemical equilibrium
dynamic equilibrium
reach equilibrium
state of equilibrium

Example sentences

"When a hot object is placed in a cooler room, heat will transfer until both reach thermal equilibrium." Describing a stable state in physics.
"The ecosystem maintained a delicate equilibrium for centuries until human intervention disrupted it." In a broader scientific context.

Memory hook

EQUAL-LIBRA-rium: Think of an EQUAL LIBRA (scales) in perfect balance. Equal Balance

When not to use

As a simple synonym for 'balance' when a more specific term like 'stability' or 'steadiness' might be more appropriate, especially outside of scientific contexts where the precise meaning of balanced forces is not implied.

Fun facts

In economics, market equilibrium is the point where supply and demand are balanced.
A tightrope walker maintains a delicate state of equilibrium.