What does "repeater" mean?

Repeater: One who, or that which, repeats. Specifically: (a) A watch with a striking apparatus which, upon pressure of a spring, will indicate the time, usually in hours and quarters. (b) A repeating firearm. (c) (Teleg.) An instrument for resending a telegraphic message automatically at an intermediate point. (d) A person who votes more than once at an election. [U.S.] (e) See Circulating decimal, under Decimal. (f) (Naut.) A pennant used to indicate that a certain flag in a hoist of signal is duplicated. Ham. Nav. Encyc.