Translation guide
The English word "expiration" has two main meanings: the end of a validity period (e.g., of a document, contract, or food) and the act of breathing out. These are expressed with different Japanese words.
Expressing that something (a document, contract, license, food, etc.) is no longer valid because its time limit has passed.
The most common and versatile term for something being past its expiration date or deadline. It can be used as a noun or with する to mean 'to expire'.
This milk is expired.
My passport has expired.
Used for the natural expiration or completion of a fixed term, especially for contracts, agreements, or official terms of office. More formal than 期限切れ.
The contract period has expired.
Means 'to become invalid' or 'to lapse', often used for legal documents, licenses, or rights. It implies a loss of effectiveness.
The license has expired (become invalid).
Specifically for food that is past its 'best before' date (賞味期限). Note: 消費期限切れ is for perishable 'use by' dates.
This can is past its best-before date, but I think it's still edible.
The act of exhaling air from the lungs.
The standard medical/physiological term for exhalation or exhaled breath. Often used in technical contexts.
Measure the amount of carbon dioxide in the expiration.
The everyday verb phrase for 'to exhale' or 'to breathe out'. Literally 'to expel breath'.
Please exhale slowly.
Can mean exhalation, but is less common than 呼気. Sometimes used in compound words.
expired gas analysis
In casual contexts, using 呼気 or 呼出 sounds overly medical. Use the verb phrase 息を吐く (to breathe out) instead.
Breathe out, then breathe in again.
賞味期限 (best-before date) is for foods that degrade slowly in quality; 消費期限 (use-by date) is for perishable foods that become unsafe. Both can be used with 切れ to mean 'expired'.
You shouldn't eat meat that is past its use-by date.