septillion

noun, plural sep·til·lions, (as after a numeral) sep·til·lion.

1. a cardinal number represented in the U.S. by 1 followed by 24 zeros, and in Great Britain by 1 followed by 42 zeros.

adjective

2. amounting to one septillion in number.

noun plural -lions or -lion

1. (in Britain, France, and Germany) the number represented as one followed by 42 zeros (10 42)
2. (in the US and Canada) the number represented as one followed by 24 zeros (10 24)Brit word: quadrillion

n.1680s, from sept- (see septi-) + (m)illion. Cf. billion.