gillion

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

   1 more example

   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.

   1968, N. W. Pirie, More About the Units (Nature vol. 220)

plural gillions

1. excessiveslangAn unspecified large number (of).

   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.

   2012, Rebecca Smith, A Bit of Earth

   1 more example

   I looked down to see my dog, Roof, short for Rufus, curled in sleep below the window, unworried by the wings of hummingbirds whirring at speeds of a gillion miles an hour as they flitted in and out of the trumpets of honeysuckle growing on the side of the house.

   2022, Frank Voss, My House Was Not a Home