n. 1
An act, process, or instance of expiring. The last emission of breath; thus, synonym of death.
n. 2
An act, process, or instance of expiring. Any other (metaphorically comparable) cessation, extinction, or ending.
n. 3
An act, process, or instance of expiring. The act or process of breathing out, or forcing air from the lungs through the nose or mouth.
crackles heard on expiration
n. 4
An act, process, or instance of expiring. A single outward breath.

Related words

Word family: expiry expire
Phrases: expiration date time until expiration

Forms

Plural: expirations → deaths, exits, deceases, demises…

Choose the right word

Expiration or End?

Expiration signifies the coming to an end in the natural course of things; as, the expiration of a year, or of a lease; it is used of things of some consequence; we do not ordinarily speak of the expiration of an hour or of a day.

J. C. Fernald, English Synonyms and Antonyms (1914)

Example sentences

termination Tom sued his employer for wrongful termination.
loss Loss of health is more serious than loss of money.
emission Filters stop emission of gas into the atmosphere.

Popularity over time

Word	1850 → 2019	Trend
expiration		falling
termination		falling
loss		steady
emission		steady

Use in printed books, per decade from 1850 to 2019.

By length

3 letters: end¹
4 letters: loss¹, exit², doom¹
5 letters: going², death¹, close¹
6 letters: breath¹, demise², expiry³
7 letters: release², passing², decease², quietus
8 letters: emission³
9 letters: breathing², departure³, cessation³
10 letters: conclusion³, exhalation⁴
11 letters: termination⁴, respiration⁴

The small number after each word is its number of syllables (exit² = 2 syllables).

In other languages

Français: expiration
Español: expiración
Català: expiració