noun
rallentando; gradually slowing down
Musical direction indicating a gradual decrease in tempo. Used in scores and musical discussion.
from Italian
この部分はラレンタンドで演奏してください。
Please play this section rallentando.
Both mean gradual slowing, but ラレンタンド is from Italian 'rallentando' and リタルダンド from 'ritardando'. In practice, they are often used interchangeably in Japanese music contexts.
Borrowed from Italian 'rallentando', the present participle of 'rallentare' (to slow down).