1. A crescendo is used for gradually getting louder, and a decrescendo or diminuendo is used for gradually getting softer.
2. piano(p) means "quiet" and forte(f) means "loud or strong".
3. pianissimo(pp) means "very quiet", fortissimo(ff) means "very loud".
4. Mezzo piano(mp) means "moderately soft", mezzo forte(mf) means "moderately loud"
5. pianissimo(pp) = very quiet
Piano(p) = quiet