:pico-: [SI: a quantifier
meaning * 10^-12]
pref. Smaller than {nano-}; used in the same rather loose
connotative way as {nano-} and {micro-}. This usage is not yet
common in the way {nano-} and {micro-} are, but should be
instantly recognizable to any hacker. See also {{quantifiers}},
{micro-}.
-- The AI Hackers Dictionary