An extremely large number. Coined by Jonathan Bowers, Picillion is based off of the metric prefix "
Pico-", meaning one trillionth (i.
e. picometer; one trillionth of a meter). Where
pico- is analogous to the metric prefixes "Deci-" (Tenth), "Centi-" (Hundredth), and "Milli-" (Thousandth), as used in the terms "Decillion" (Tenth '-illion'), "Centillion" (Hundredth '-illion'), and Millillion/Millinillion (Thousandth 'illion').
Picillion is equal to
10^3⋅
10^12+3, or
10^3,000,000,000,000+3. That is one, followed by three trillion and three zeroes.
"If micrillion is the millionth
number ending in '-illion', and nanillion is the billionth
number ending in '-illion', then what do we call the trillionth
number ending in '-illion'?"
"A picillion."