I. |rälən.|tän(ˌ)dō, |ralən.|tan- adverb (or adjective)
Etymology: Italian, literally, slowing down, verbal of rallentare to relax, slow down again, from r- re- + allentare to slow down, from Late Latin, from Latin al- ad- + lentus pliant, tough, slow — more at lithe
: with a gradual decrease or slackening in tempo : ritardando — used as a direction in music
II. noun
( -s )
1. : a gradually slackening musical tempo
2. : a musical passage or movement gradually decreasing in tempo