crescendo (or cresc.)
gradually getting louder
decrescendo (or decresc.)
gradually getting quieter
diminuendo (or dim.)
gradually getting quieter
Forte (f)
loud
Fortissimo (ff)
very loud
mezzo forte (mf)
moderately loud (half loud)
mezzo piano (mp)
moderately quiet (half quiet)
Piano (p)
quiet
Pianissimo (pp)
very quiet
Fortepiano (fp)
loud, then soft
Forzando (fz)
forced, accented
Sforzando, sforzato (sf, sfz)
forced, accented