Adjective: quintillionth
- The ordinal number of one quintillion in counting order
"The quintillionth atom in the sample was analysed"
- One part in a quintillion equal parts
"The experiment measured changes at the one-quintillionth scale";
- one-quintillionth
Derived forms: quintillionths
See also: ordinal
Type of: common fraction, simple fraction, vulgar fraction [Brit]
Encyclopedia: Quintillionth