- a combining form meaning “one trillionth” (10−12): picogram.
Origin of pico-
- denoting 10 –12picofarad Symbol: p
Word Origin and History for pico-
word-forming element used in making names for very small unites of measure, 1915 (formally adopted c.1952 as a scientific prefix meaning "one trillionth"), from Spanish pico "a little over, a small balance," literally "sharp point, beak," of Celtic origin (cf. Gaulish beccus "beak").
- One-trillionth (10-12):picogram.
- Very small:picornavirus.