lifetime

The word “lifetime” means the entire duration of someone's or something's life. In plain terms, the whole span of time someone or something is alive or in existence.

“Lifetime” is pronounced LYF-tym (/ˈlaɪf.taɪm/ in IPA).

Here is “lifetime” used in a sentence: “She saw huge technological change in her lifetime.”

“Lifetime” is a noun.

The word “lifetime” comes from Middle English. From Middle English lyftyme, formed from life + time.

“Lifetime” is a fairly common word in modern English, usually learned at around the B2 level.

A lifetime is the entire duration of a particular life, viewed as the period in which things happen: "She saw enormous change in her lifetime." A lifespan is the length of time a person, animal, or object lives or lasts, usually thought of as a measurable figure, as in "an average lifespan of ten years."

The standard spelling is one word: "lifetime." Writing it as two words is considered an error in modern English, whether it is used as a noun ("a lifetime of work") or before another noun ("a lifetime guarantee").

Hyphenate it when the phrase works as an adjective directly before a noun: "a once-in-a-lifetime opportunity." Leave it unhyphenated when it stands alone as a phrase: "An offer like this comes along once in a lifetime." Either way, it describes something so rare it may only happen during one entire life.

Yes. "Lifetime" covers the entire duration of anything's existence or usefulness, not just a person's life. It is common in technical and commercial contexts, as in "the lifetime of a battery" or "a lifetime warranty."