I. ˈ ̷ ̷ˌ ̷ ̷ noun
Etymology: tell (I) + tale (after the phrase tell tales )
1. : one who officiously gives information of the private concerns of others : one who tells what should be withheld : talebearer , informer
2. : something that serves to disclose something else or give information : hint , indication
3. : a device for indicating or recording something: as
a. : a device for keeping a check on employees (as factory hands, drivers, check takers) ; especially : time clock
b.
(1) : a mechanical attachment to a ship's steering wheel that shows the position of the helm or rudder
(2) : a compass in the cabin where the captain can see it
(3) : a wind direction indicator in the form of a ribbon or similar piece of material
c. : a small overflow pipe that indicates by dripping when a tank is full
d. : a strip of metal on the front wall of a racquets or squash court to a height of from 2 to 2 1/2 feet above the ground over which the ball must be hit
e. : a device serving as a warning on a railroad: as
(1) : a row of long strips (as of rope) hung from a bar over the tracks to warn freight brakemen of their approach to a low overhead bridge
(2) : a low fender placed near a hole in the permanent way to warn trackwalkers and others
4. : tattler 2
II. adjective
1. : officiously telling what one should hold secret or in confidence : informing , talebearing
2. : disclosing or indicating something often of a private or secret nature : betraying, revealing
there was only that telltale patch of oil on the water to mark where he had disappeared — Oxford Book of English Talk
scanning each vein of rock for the telltale glint of yellow metal — R.A.Billington
a hair-brush can be a telltale thing when a fellow begins to lose his hair — Valentine Williams
months of telltale psychological preparation must precede an aggressive war — M.W.Straight
3.
a. : being any of various devices for giving warning or keeping a watch or record
a telltale indicator in the bureau, calling attention of the management only in case a bell has rung — J.R.Stuart
a telltale panel of lights indicating everything from motor heat to whether the stewardess shut the door — H.G.Armstrong
b. : being a process or operation by which such a device warns or records
a telltale operation
• tell·tale·ly adverb
III. transitive verb
( -ed/-ing/-s )
Etymology: telltale (II)
: to perform a telltale operation on
telltale forgings to determine whether there is sufficient stock for finishing