-illion

Back-formation from million, billion, trillion, quadrillion, each from French.

-illion

1. Combined with Latin prefixes for names of integers in order to form names of powers of a million or of a thousand greater than 1,000,000. Thus we have the names billion, trillion, etc.
2. Added to various nonsense syllables to indicate an arbitrarily very large number.

• The words formed by combining the Latin prefix for the name of an integer ${\displaystyle n}$ (${\displaystyle n>1}$ ) with this suffix may mean ${\displaystyle 1,000,000^{n}}$ or ${\displaystyle 1000^{n+1}}$ depending on national practices. Hence billion can mean “million million” or “thousand million”. See the usage notes at Wiktionary’s appendix on numbers for more information.

• Category:English words suffixed with -illion

• Indefinite and fictitious numbers on Wikipedia.Wikipedia