pico- [PEE koh]  (Italian: very small or from Spanish, "beak,
tip, very small"; and from Latin, beccus, beak; also, a decimal
prefix used in the international metric system for measurements)
This prefix is used in metric [decimal] system as trillionth
[U.S.] and billionth part [U.K.], 10-12 [0.000 000 000 001]. The
metric symbol for pico- is p.  A metric unit of mass equal to
10-12 gram or one millionth of a microgram. picokelvin (pK)
Scientists at the Massachusetts Institute of Technology (MIT),
in Cambridge, USA, led by Aaron Leanhardt, announced in
September, 2003, that they had achieved a temperature of 450
picokelvin above absolute zero (0.000 000 000 45 degrees above
absolute zero). This is considered the lowest man-made
temperature to have been achieved.  picopicogram, ppg A unit of
mass or weight equal to 10-24 grams. Tiny planktonic organisms
ranging in size from 0.2 to 2.0 micrometers. And little fleas
have lesser fleas, and ad infinitum. — Augustus de Morgan,
noting the expanding scales of life a