Standard Lemma guide

theta

noun · 8 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

Each Play button uses your device's default local English voice, or a natural local fallback. The selected voice name appears after playback. This is synthesized speech, not a source recording.

  • UK: /ˈθiːtə/
  • Canada, US: /ˈθeɪtə/
  • Canada, US: [ˈθeɪɾə]
  • Canada, US: /ˈθitə/
  • California: Recorded audio is listed in the source snapshot.
  • Australian, New-Zealand: /ˈθæɪtə/
  • Australian, New-Zealand: [ˈθæɪɾə]
  • Hong-Kong: /ˈθeɪ.ta/
  • Hong-Kong: [fei̯˥ thaː˩]
  • rhymes with -iːtə
  • rhymes with -eɪtə
  • US: Recorded audio is listed in the source snapshot.
  • CMU ARPABET: TH EY1 T AH0 Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.

1

noun

Meaning 1

The eighth letter of the Modern Greek alphabet, ninth in Old Greek: Θ, θ.

Definition source: English Wiktionary via Wiktextract

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

2

noun

Meaning 2

The measure of an angle.

Definition source: English Wiktionary via Wiktextract

Topics: mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

3

noun

Meaning 3

Pitch angle; the angle between an aircraft's longitudinal axis and the horizontal plane.

Definition source: English Wiktionary via Wiktextract

Usage: broadly

Topics: aeronautics, aerospace, aviation, business, engineering, natural-sciences, physical-sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: deck angle

Antonyms: none provided

4

noun

Meaning 4

The sensitivity of the value of a derivative with respect to time; the "time decay".

Definition source: English Wiktionary via Wiktextract

Topics: business, finance

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

5

noun

Meaning 5

Designating a level of brain activity as measured by electroencephalography having a frequency of between four and seven cycles per second (associated with drowsiness in adults).

Definition source: English Wiktionary via Wiktextract

Topics: biology, natural-sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

6

noun

Meaning 6

The voiceless dental fricative represented by θ.

Definition source: English Wiktionary via Wiktextract

Topics: human-sciences, linguistics, phonology, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

7

noun

Meaning 7

A member of the Kappa Alpha Theta sorority.

Definition source: English Wiktionary via Wiktextract

Usage: US, colloquial

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

8

noun

Meaning 8

the 8th letter of the Greek alphabet

Definition source: Princeton WordNet 3.0

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

Broader terms: letter, letter of the alphabet, alphabetic character

History

Etymology

Borrowed from Ancient Greek θῆτα (thêta).

Across languages

Translations

37 source translations are retained for this English entry.

  • Arabic: ثِيتَا (ṯītā) — Greek letter
  • Arabic: ثيتا (ṯīta) — Greek letter
  • Aramaic: ܛܝܬܐ (ṯita) — Greek letter
  • Armenian: թետա (tʻeta) — Greek letter
  • Asturian: theta — Greek letter
  • Catalan: theta — Greek letter
  • Chinese Mandarin: 西塔 (xītǎ) — Greek letter
  • Danish: theta — Greek letter
  • Dutch: thèta — Greek letter
  • Esperanto: teto — Greek letter
  • Finnish: theeta — Greek letter
  • French: thêta — Greek letter
  • German: Theta — Greek letter
  • Greek: θήτα (thíta) — Greek letter
  • Ancient Greek: θῆτα (thêta) — Greek letter
  • Hebrew: טֵיתָא (téta) — Greek letter
  • Hungarian: théta — Greek letter
  • Icelandic: þeta — Greek letter
  • Interlingua: theta — Greek letter
  • Japanese: テータ (tēta) — Greek letter
  • Japanese: シータ (shīta) — Greek letter
  • Korean: 테타 (teta) — Greek letter
  • Malay: teta — Greek letter
  • Māori: heitā — Greek letter
  • Marathi: थीटा (thīṭā) — Greek letter
  • Marathi: थेटा (theṭā) — Greek letter
  • Polish: theta — Greek letter
  • Portuguese: teta — Greek letter
  • Russian: те́та (tɛ́ta) — Greek letter
  • Russian: фи́та (fíta) — Greek letter
  • Spanish: zeta — Greek letter
  • Spanish: theta — Greek letter
  • Spanish: tita — Greek letter
  • Swedish: theta — Greek letter
  • Tagalog: teta — Greek letter
  • Turkish: teta — Greek letter
  • Ukrainian: те́та (téta) — Greek letter
Real reading context

theta in complete knowledge articles