theine

/ˈθiː.iːn/

//ˈθiː.iːn// noun

"theine" is a 6-letter English headword indexed on PlainSpell.

The verdict

“theine” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
6
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Caffeine when present in tea.

Corpus desk

Index EN-theine · theine · English

theine · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-LONG 6 letters
  • VOW-3 3 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "T" thin
  • PHOTO-UNK Peer pending

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Key facts for theine
PropertyValue
Headwordtheine
LanguageEnglish
Part of speechNoun
IPA/ˈθiː.iːn/
Letters6
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “theine” in English

theineranks outside the top 100,000 English headwords, in the long tail of specialist, archaic, or seldom-used vocabulary, exactly the territory where a reader stops mid-sentence to double-check spelling.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

theine is uncommon English outside the top frequency list, classed as anoun, transcribed /ˈθiː.iːn/. Rarity is why readers land here mid-draft. Gloss: "Caffeine when present in tea.".

theine has no tracked misspelling variants, and the word's spelling is regular enough that our generator found nothing worth flagging. No confusable counterpart is on file for this word, since nothing in our dataset looks or sounds close enough to cause mix-ups.

Etymologically, the entry records: From French théine. The correct English form is theine, spelled T-H-E-I-N-E.

Definition

  1. 1
    Caffeine when present in tea.

Recorded use

Wiktionary example

These source excerpts show how theine appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. Caffeine is called guaranine when found in guarana, mateine when found in mate and theine when found in tea. There is far more caffeine in coffees than in teas.

Etymology

From French théine.

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "theine"?
"theine" is spelled T-H-E-I-N-E. The IPA pronunciation is /ˈθiː.iːn/.
What does "theine" mean?
As a noun, "theine" means: Caffeine when present in tea.
How do you pronounce "theine"?
The IPA (International Phonetic Alphabet) transcription for "theine" is /ˈθiː.iːn/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "theine"?
From French théine. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list