-illion

suffix

Combined with Latin prefixes for names of integers in order to form names of powers of a million.

“bajillion, gazillion”

OriginEnglish millionbf. ← Middle English milioun →
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Meanings

suffix
  1. Combined with Latin prefixes for names of integers in order to form names of powers of a million.

    bi- + -illion → billion

    1 more example

    tri- + -illion → trillion

  2. Added to various nonsense syllables to indicate an arbitrarily very large number.

    bajillion, gazillion

Origin

  1. Middle Englishmilioun
  2. Englishmillionbf.
  3. English-illion

Back-formation from million, then used in billion, trillion, quadrillion, each from French, ultimately from Italian mille (“thousand”) and the augmentative suffix -one. -illion was segmented from million as if mi- was a prefix, and -illion the stem.

Full word history & related roots →

Translations

Esperanto -iliono
  • -ilionosuffix forming names of powers of a million or of a thousand greater than 1,000,000
French -illion
  • -illionsuffix forming names of powers of a million or of a thousand greater than 1,000,000
Polish -ilion
  • -ilionsuffix forming names of powers of a million or of a thousand greater than 1,000,000
Russian -ард, -иллион
  • -ард (-ard)suffix forming names of powers of a million or of a thousand greater than 1,000,000
  • -иллион (-illion)suffix forming names of powers of a million or of a thousand greater than 1,000,000
Turkish -ar, -ilyon
  • -arsuffix forming names of powers of a million or of a thousand greater than 1,000,000
  • -ilyonsuffix forming names of powers of a million or of a thousand greater than 1,000,000
Cite this entry
APA

-illion. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/-illion

MLA

“-illion.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/-illion. Accessed November 3, 2026.

Chicago

WatkinsX Dictionary, s.v. “-illion,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/-illion.

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