decillion

UK: /dɪˈsɪljən/ US: (di sil′yən)

WordReference Random House Unabridged Dictionary of American English © 2025

de•cil•lion  (di sil′yən), n. 

1. Mathematics a cardinal number represented in the U.S. by 1 followed by 33 zeros, and in Great Britain by 1 followed by 60 zeros.

adj. 

2. Mathematics amounting to one decillion in number.

• Latin dec(em) ten + -illion, as in million
• 1835–45

de•cil′lionth, adj., n. 

Collins Concise English Dictionary © HarperCollins Publishers::

decillion / dɪˈsɪljən/ noun

1. (in Britain, France, and Germany) the number represented as one followed by 60 zeros (10⁶⁰)
2. (in the US and Canada) the number represented as one followed by 33 zeros (10³³)

Etymology: 19th Century: from Latin decem ten + -illion as in million

deˈcillionth adjective