# theta
## English
### Etymology

Borrowed from Ancient Greek θῆτα (thêta).

### Pronunciation

* (UK) IPA: /ˈθiːtə/
* (US, Canada) IPA: /ˈθeɪtə/, /ˈθitə/
* Audio (US):(file)
* (Hong Kong) IPA: /ˈθeɪ.ta/, [fei̯˥ tʰaː˩]
* Rhymes: -iːtə, -eɪtə

### Noun

theta (plural thetas)
* The eighth letter of the Modern Greek alphabet, ninth in Old Greek: Θ, θ.
* (mathematics) The measure of an angle.
* (aviation, by extension) Pitch angle; the angle between an aircraft's longitudinal axis and the horizontal plane.
    Synonym: deck angle
* (finance) The sensitivity of the value of a derivative with respect to time; the "time decay".
* (biology) 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).
** 2018 September 19, Meghan O'Gieblyn, “The Most Unread Book Ever Acclaimed”, in The Paris Review:The reader is less likely to throw the book down in a fit of disgust than she is to be lulled into a theta state, a highway hypnosis induced by page after page of incantatory prose.
* (phonology) The voiceless dental fricative represented by θ.

#### Hypernyms

* (measure of derivative price sensitivity): Greeks (includes list of coordinate terms)

#### Coordinate terms

(pitch angle of an aircraft):
* alpha
* beta
* gamma

#### Derived terms

* Ramanujan theta function
* theta-delta
* theta function
* theta graph
* theta join
* theta meditation
* thetan
* theta pinch
* theta rhythm
* theta role
* theta wave

#### Descendants

* → Malay: teta

#### See also

* (Greek-script letter names) alpha, beta, gamma, delta, epsilon, zeta, eta, theta, iota, kappa, lambda, mu, nu, xi, omicron, pi, rho, sigma, tau, upsilon, phi, chi, psi, omega

## Catalan
### Etymology

Borrowed from Ancient Greek θῆτα (thêta).

### Pronunciation

* IPA: (Central, Balearic) [ˈtɛ.tə]
* IPA: (Valencia) [ˈte.ta]

### Noun

theta f (plural thetes)
* theta; the Greek letter Θ (lowercase θ)

### Further reading

* “theta” in Diccionari de la llengua catalana, segona edició, Institut d’Estudis Catalans.
* “theta”, in Gran Diccionari de la Llengua Catalana, Grup Enciclopèdia Catalana, 2025
* “theta” in Diccionari normatiu valencià, Acadèmia Valenciana de la Llengua.

## Czech
### Alternative forms

* théta

### Etymology

Borrowed from Ancient Greek θῆτα (thêta).

### Pronunciation

* IPA: [ˈtxɛːta]
* IPA: [ˈtɛːta]

### Noun

theta n or f
* theta (Greek letter)

#### Declension

when feminine:
Indeclinable when neuter.

## Italian
### Etymology

From the Ancient Greek θῆτα (thêta).

### Pronunciation

* IPA: /ˈtɛ.ta/
* Rhymes: -ɛta
* Hyphenation: thè‧ta

### Noun

theta m or f (invariable)
* theta (Greek letter)

### References

* ↑ theta in Treccani.it – Vocabolario Treccani on line, Istituto dell'Enciclopedia Italiana

## Pali
### Alternative forms

* 𑀣𑁂𑀢 (Brahmi script)
* थेत (Devanagari script)
* থেত (Bengali script)
* ථෙත (Sinhalese script)
* ထေတ (Burmese script)
* เถต or เถตะ (Thai script)
* ᨳᩮᨲ (Tai Tham script)
* ເຖຕ or ເຖຕະ (Lao script)
* ថេត (Khmer script)
* 𑄗𑄬𑄖 (Chakma script)

### Adjective

theta
* reliable
* trustworthy

## Polish
### Etymology

Learned borrowing from Ancient Greek θῆτα (thêta), from Phoenician 𐤈 (ṭ‬ /⁠ṭēt⁠/).

### Pronunciation

* IPA: /ˈtɛ.ta/
* Audio:(file)
* Rhymes: -ɛta
* Syllabification: the‧ta

### Noun

theta f
* theta (Greek letter Θ, θ)

#### Declension
### Further reading

* theta in Polish dictionaries at PWN

## Portuguese
### Noun

theta f (plural thetas)
* Pre-reform spelling (used until 1943 in Brazil and 1911 in Portugal) of teta.

## Spanish
### Etymology

Borrowed from Ancient Greek θῆτα (thêta).

### Pronunciation

* IPA: /ˈteta/ [ˈt̪e.t̪a]
** Rhymes: -eta
* IPA: /ˈtita/ [ˈt̪i.t̪a]
** Rhymes: -ita

### Noun

theta f (plural thetas)
* theta; the Greek letter Θ, θ
    Synonyms: zeta, tita