- pico-
[pico- 词源字典]
- 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 (compare Gaulish beccus "beak").[pico- etymology, pico- origin, 英语词源]