thio-

UK/θʌɪ.ə(ʊ)/US/θaɪ.oʊ/US/θaɪ.ə/

prefix

containing sulfur, especially a compound in which oxygen has been replaced by this element

OriginAncient Greek θεῖον (theîon) ← Proto-Indo-European *dʰewh₂-der.? →
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Meanings

prefix

alternative before vowel thi-

  1. chemistrycontaining sulfur, especially a compound in which oxygen has been replaced by this element

    Chalcogen analogues of monocarboxylic acids with retained names may also be named by placing the prefix ‘thio’, ‘seleno’, or ‘telluro’ in front of the name of the acid.

    2013, Henri A. Favre and Warren H. Powell, eds., Nomenclature of Organic Chemistry, 765

Origin

  1. Proto-Indo-European*dʰewh₂-der.?
  2. Ancient Greekθέειον (théeion)
  3. Ancient Greekθεῖον (theîon)
  4. Englishthio-

Derived from Ancient Greek θεῖον (theîon, “sulfur”).

More words from Ancient Greek

Full word history & related roots →
Cite this entry
APA

thio-. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/thio-

MLA

“thio-.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/thio-. Accessed November 2, 2026.

Chicago

WatkinsX Dictionary, s.v. “thio-,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/thio-.

Source: thio- on Wiktionary, CC BY-SA 4.0.