Life span or lifespan?
life span is a noun meaning “Alternative spelling of lifespan”; lifespan is a noun meaning “The length of time for which an organism lives”. Wiktionary gives them as spellings of the same word. life span is written as two words and lifespan as one word; they are used differently.
What is the difference between life span and lifespan?
| life span | lifespan | |
|---|---|---|
| Part of speech | noun | noun |
| Meaning | Alternative spelling of lifespan | The length of time for which an organism lives The length of time for which something exists or is current, valid, or usable |
| Example | none recorded | Meronym: healthspan |
| Forms | none | lifespans |
| Pronunciation | not recorded | /ˈlaɪf.spæn/ |
| In writing | not counted (the list counts single words) | 2.3 times per million words |
Sources: life span and lifespan in the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
Every current meaning of life span and lifespan
life span
- 1
Alternative spelling of lifespan
lifespan
- 1
The length of time for which an organism lives
Meronym: healthspan
- 2
The length of time for which something exists or is current, valid, or usable
Source: the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); obsolete, archaic, dialect and rare senses left out.
Which is more common, life span or lifespan?
life span is a phrase, which the list of single words does not count; lifespan 2.3 times per million words.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How many people search life span vs lifespan?
“life span vs lifespan” is searched about 30 times a month on Google and 10 on Bing in the United States. Google counts close variants of a query together (“lifespan vs life span”, “life span or lifespan”).
Sources: Google Ads keyword data through DataForSEO and Microsoft Advertising keyword data through DataForSEO, the average month from September 2025 to August 2026.