quintillionth

quin·til·lionth

Q0037400 (kwĭn-tĭl′yənth)n.1. The ordinal number matching the number quintillion in a series.2. One of a quintillion equal parts.

quin·til′lionth adv. & adj.

Thesaurus

Noun	1.	quintillionth - one part in a quintillion equal partsone-quintillionthcommon fraction, simple fraction - the quotient of two integers
Adj.	1.	quintillionth - the ordinal number of one quintillion in counting orderordinal - being or denoting a numerical order in a series; "ordinal numbers"; "held an ordinal rank of seventh"