Gillion

//ˈɡɪljən// noun, num, slang

noun, num, slang ·Moderate ·College level

Definitions

Noun
  1. 1
    An unspecified large number (of). excessive, slang

    "At Guy's school there had been an outdoor pool, in use from April to October, a watery grave for a billion insects, or quite possibly a gillion or a squillion. The bright turquoise lining had wrinkled under the children's feet."

Numeral
  1. 1
    A thousand million, proposed as an alternative to the (now little used) British milliard and the (ambiguous, in the UK) US billion. British, rare

    "The internationally agreed symbol for 10^6 is M and this is the initial letter of million. Would it not be logical and convenient to turn this happy accident into a principle and use G, the internationally agreed symbol for 10^9, as the initial letter of the word for 1,000,000,000? That number would thus be called a gillion. Whether the g should be hard or soft is a matter of opinion. I incline to hard because of the derivation from giga."

Example

More examples

"The internationally agreed symbol for 10^6 is M and this is the initial letter of million. Would it not be logical and convenient to turn this happy accident into a principle and use G, the internationally agreed symbol for 10^9, as the initial letter of the word for 1,000,000,000? That number would thus be called a gillion. Whether the g should be hard or soft is a matter of opinion. I incline to hard because of the derivation from giga."

Etymology

From gi(ga)- + -illion. Modelled after million, billion etc. Compare also jillion.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.