What does expiration mean?
Expiration is a noun with two principal meanings. Its dominant modern sense is the ending of a fixed period of validity — the moment at which a contract, passport, subscription, warranty, or food item ceases to be effective or usable, commonly encountered in the phrase "expiration date." Its older, more technical sense describes the act of breathing out, the expulsion of air from the lungs, a usage now largely confined to medical and scientific writing. The word derives from Latin exspirare, "to breathe out," which also underlies "spirit" — a reminder that breath and life were long considered inseparable. In formal registers, "expiration" conveys finality and legal precision; British English frequently prefers "expiry." Related derivatives include the verb "expire" and the adjective "expired," making the word family useful across legal, commercial, and everyday contexts.
The ending of a fixed period during which something remains valid, effective, or usable.
"The expiration of his visa left him just two weeks to leave the country."
Frequently used attributively in "expiration date."
The act of expelling air from the lungs; exhalation.
"During meditation, focus on the length of each expiration."
Chiefly medical or physiological register; "exhalation" is the more common everyday term.
Rarely used in the plural; typically appears only when referring to multiple distinct instances of expiry or breaths.
"The contract tracked all expirations of subsidiary agreements over the decade."
"Expiration" literally means "breathing out" — the same Latin root that gives us "spirit," originally meaning breath.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of expiration
Expiration comes from Latin exspirare, formed from ex- ("out") and spirare ("to breathe"), originally meaning the act of breathing one's last breath. English adopted the word via Old French in the late Middle Ages, initially retaining this literal and figurative sense of dying. Over time its meaning broadened to the mere cessation of validity — the moment a term of years, contract, or product life runs out — while the physiological sense of exhaling survives mainly in technical usage. It shares its Latin root with words like respire, inspire, and spirit.
Related word forms
How expiration is actually used
In everyday use, "expiration" almost always refers to deadlines or validity dates. In medical and physiological contexts it specifically denotes breathing out, where "exhalation" is the more common everyday alternative. In British English, "expiry" is often preferred for dates.
Easily confused with expiration
Perspiration means sweat, while expiration refers to the ending of something or the act of breathing out.
Aspiration means a hope or ambition (or the act of drawing breath in), whereas expiration concerns endings and breathing out.