rin·for·zan·do (rēn'fôr-tsän'dō) adv.
& adj.Music Abbr. rf or rfz With a sudden increase of emphasis. Used chiefly as a direction.
[Italian, present participle of rinforzare, to reinforce, strengthen : ri-, again (from Latin re-; see re-) + inforzare, to enforce, make strong (from Old French enforcier; see enforce).]