repetend

n. 循环节, 叠句

rep.e.tend

n.（名词）
A word, sound, or phrase that is repeated; a refrain.
叠句：重复的词语、声音或短语；重复句
Mathematics The digit or group of digits that repeats infinitely in a repeating decimal.
【数学】 循环节：在循环小数中无限重复的数节或一组数节

来源：
From Latin repetendum [neuter gerundive of] repetere [to repeat] * see repeat
源自 拉丁语 repetendum [] repetere的中性动形词 [重复] *参见 repeat