Noun. 1. jillion - a very large indefinite number (usually hyperbole); "there were millions of flies" gazillion, trillion, zillion, million, billion. large indefinite amount, large indefinite quantity - an indefinite quantity that is above the average in size or magnitude.

How much is a gillion?

/ (ˈdʒɪljən) / noun. British (no longer in technical use) one thousand millionUS and Canadian equivalent: billion.

What is a gazillion mean?

informal. : a huge, unspecified number : zillion According to William Miller, Jr., VMD, a professor of dermatology at Cornell University's College of Veterinary Medicine, there are "gazillions" of different types of fungi existing in nature, including molds, yeasts, mildews and so forth.