ticktack

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A steady ticking sound, as of a clock.
2. n. A prankster's device for tapping on a door or window from a distance.

Century Dictionary and Cyclopedia

1. n. A pulsating sound like that made by a clock or watch; a ticking.
2. n. Specifically, the sound of the beating of the heart.
3. n. A device employed in playing certain practical jokes, consisting of a small weight so fastened that one at a distance can, by pulling a string, cause the weight to tap against the house or window.
4. With a sound resembling the beating of a watch.
5. n. A complicated kind of backgammon, played both with men and with pegs. Compare trick-track, and see the third quotation below.

Wiktionary

1. interj. Dated form of tick tock.

GNU Webster's 1913

1. n. A noise like that made by a clock or a watch.
2. n. A kind of backgammon played both with men and pegs; tricktrack.
3. adv. With a ticking noise, like that of a watch.

WordNet 3.0

1. n. system of signalling by hand signs used by bookmakers at racetracks
2. v. make a sound like a clock or a timer