Misc: What reduction is indicated when a measurement is prefixd by the word pico?

Questions

- Abbreviation for pianissimo, very soft.?

(It.) - Impetuously.?

(It.) - Precise.?

- Term describing music before Haydn and Mozart and also (more vaguely) describing music before Bach.?

- An introductory piece or movement before a fugue, an act of an opera etc. Chopin and other later composers wrote preludes as short, independent piano pieces in one movement.?