half-life
Definition, pronunciation, etymology, and usage for the English word. Free spelling reference powered by Wiktionary.
Detailed reference entry for the English word "half-life", 9-letters, with pronunciation in International Phonetic Alphabet notation, etymology traced through Germanic and Romance roots where applicable, common misspelling variants catalogued from Wiktionary, and usage frequency ranked against an open word-frequency list covering the top 100,000 English words. PlainSpell covers English, Spanish, Portuguese, French, and German spelling with confusable-pair detection that highlights visually and phonetically similar words. This entry for "half-life" includes synonyms, antonyms, homophones, and cross-language translation pointers sourced from Wiktionary via the kaikki.org extract. Whether you are verifying the correct spelling of "half-life" for academic writing, checking homophone confusion, or exploring etymological origins, this page provides a citation-backed, free reference that requires no sign-up.
The verdict
“half-life” is outside the top-ranked English vocabulary, used as a noun — the kind of word writers most often double-check.
- Unranked
- below top-frequency English
- 9
- letters
Dominant Wiktionary sense: The time required for half the nuclei in a sample of an isotope to undergo radioactive decay.
Compare similar words
See how half-life compares against similar English words.
Browse all word comparisons →| Property | Value |
|---|---|
| Headword | half-life |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈhæfˌlaɪf/ |
| Letters | 9 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “half-life” sits in English frequency
Spelling & Dictionary Insight
The English entry for half-life is 9 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˈhæfˌlaɪf/. It sits outside the most-frequent rank tiers, which is often why uncommon words generate more spelling variants per reader. Wiktionary records 4 distinct senses for this headword, so context determines which meaning a reader should apply.
No misspelling variants are generated for half-life in our index, suggesting the orthography follows predictable English patterns. It is not paired with a close-neighbour confusable in our dataset, which tends to mean the word is visually distinctive enough to stand on its own.
Etymologically, the entry records: From half- + life. Root origin matters for spelling because borrowed morphemes (Greek, Latin, Old French, Old English) carry their source-language orthographic conventions into modern English, which is why historical etymology is often the cleanest predictor of whether a cluster like "-ough", "-eau", or "-tion" will appear. For readers arriving here from a spelling check, the authoritative guidance is: the correct English form is half-life, spelled H-A-L-F---L-I-F-E, and any other sequence of those letters, regardless of how natural it feels, is a misspelling in standard orthography.
Definition
- 1The time required for half the nuclei in a sample of an isotope to undergo radioactive decay.
- 2In a chemical reaction, the time required for the concentration of a reactant to fall from a chosen value to half that value.
- 3The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacological, physiologic, or radiological activity.
- 4The amount of time it takes for an idea or a fashion to lose half of its influential power.
Etymology
From half- + life.
This word in other languages
Frequently Asked Questions
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Using “half-life”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is H-A-L-F---L-I-F-E — every other letter order is a misspelling in standard orthography.
- Say it as /ˈhæfˌlaɪf/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Browse more English words and confusable pairs in the same reference. English words
Nearby English words
Other entries that begin with the letter H in our English index: