WordReference Random House Unabridged Dictionary of American English © 2025
sex•de•cil•lion
(seks′di sil′yən),USA pronunciation n., pl. -lions, (as after a numeral) -lion, adj.
n.
adj.
n.
- a cardinal number represented in the U.S. by 1 followed by 51 zeros, and in Great Britain by 1 followed by 96 zeros.
adj.
- amounting to one sexdecillion in number.
- sex- + decillion 1935–40