n. 循环节, 叠句

Repetend \Rep`e*tend\ (r?p`?-t?nd"), n. [L. repetendus to be
repeated, fr. repetere to repeat.] (Math.)
That part of a circulating decimal which recurs continually,
ad infinitum: -- sometimes indicated by a dot over the first
and last figures; thus, in the circulating decimal .728328328
+ (otherwise .7..8...), the repetend is 283.

Decimal \Dec"i*mal\, n.
A number expressed in the scale of tens; specifically, and
almost exclusively, used as synonymous with a decimal
fraction.

{Circulating decimal}, or {Circulatory decimal}, a decimal
fraction in which the same figure, or set of figures, is
constantly repeated; as, 0.354354354; -- called also
{recurring decimal}, {repeating decimal}, and {repetend}.