equation
Pluralequations
- 1A mathematical statement that two expressions have the same value, written as the two expressions joined by an equal sign.
She balanced the equation by adding a coefficient to each side.
Physicists use equations to describe how objects move through space.
Note
Mathematics gives the word its sharpest outline. An equation is a claim of equality, and solving one means finding the values of any unknowns that make both sides take the same value. In a larger problem, each equation captures one aspect, so several usually work together before the problem yields. Compare the general act of equating: there a person pairs two things, while here the equality is written out with an equal sign.
- 2The act or process of treating two or more things as equal, or the state of those things being identical.
His equation of wealth with virtue troubled the philosophers in the room.
The constant equation of silence with agreement leads to misunderstandings.
Similaridentification, conflation, association
Note
Here the word is still plainly the noun of equate, formed with -ion. Latin aequātiō meant "an equalizing", and this sense keeps that act of making things equal. Its working construction is equation of one thing with another, as when Eva Illouz, in Why Love Hurts (2013), writes of "the cultural equation of love with suffering". The pairing is usually something a person or a culture asserts, not something proved.
- 3A small adjustment that compensates for consistent bias in the results of an observation.
The astronomer applied an equation to account for the instrument's slow drift.
Tables of equations let observers correct raw timings for systematic bias.
Similarcorrection
Note
Astronomy uses the word for a small correction added to a measured quantity, offsetting known systematic error so the result lands closer to the true value. The Latin sense of "an equalizing" behind the act of equating is most literal here, because the correction evens an observation out. The best-known survivor is the equation of time, which adjusts apparent solar time to mean time.
Practice
Can you tell the meanings of equation apart? Answer 2 quick questions from this page, or write your own sentence and AI will check it.
Origin
It comes from Old French, from Latin aequātiō ("an equalizing"). It can be analyzed as equate plus the suffix -ion.