theta

Borrowed from Ancient Greek θῆτα (thêta).

• (UK) IPA^(key): /ˈθiːtə/
• (US) IPA^(key): /ˈθeɪtə/

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theta (plural thetas)

1. The eighth letter οf the Modern Greek alphabet, ninth in Old Greek: Θ, θ.
2. (mathematics) The measure of an angle.
3. (finance) The sensitivity of the value of a derivative with respect to time; the "time decay".
4. (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, Meghan O'Gieblyn, "The Most Unread Book Ever Acclaimed", The Paris Review, 19 September:

     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.

5. (phonology) The voiceless dental fricative represented by θ.

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

• theta wave
• thetan

From the Ancient Greek θῆτα (thêta).

• (Balearic, Central) IPA^(key): /ˈtɛ.tə/
• (Valencian) IPA^(key): /ˈtɛ.ta/

theta f (plural thetes)

1. Theta; the Greek letter Θ (lowercase θ).

• théta

From the Ancient Greek θῆτα (thêta).

theta n

1. theta (Greek letter)

From the Ancient Greek θῆτα (thêta).

theta m or f (invariable)

1. theta (Greek letter)

theta

1. reliable
2. trustworthy

theta f (plural thetas)

1. Obsolete spelling of teta (used in Portugal until September 1911 and died out in Brazil during the 1920s).

From the Ancient Greek θῆτα (thêta).

• IPA^(key): /ˈteta/, [ˈt̪et̪a]

theta f (plural thetas)

1. theta; the Greek letter Θ, θ

• zeta
• tita