telltale

What it means

1. One who divulges private information with intent to hurt others.

   The Chinese girls who saw me yesterday are telltales. I'd better wait till dark.

   2008, Fleur Yano, Collected Writings of Flora Belle Jan, page 112

   4 more examples

   Your husband is at hand; I heare his Trumpet, / We are not tell-tales, Madam; feare you not.

   c. 1596–1598 (date written), William Shakespeare, “The Merchant of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act V, scene i], page 183

   There were some ill-natured people —tell-tales—it seemed, in Tamai; and hence there was a deal of mystery about getting up the dance.

   1846, Herman Melville, Typee

   Louis tells me that the gossip of the sailors finds its way aft, and that two of the telltales have been badly beaten by their mates.

   1904, Jack London, The Sea-Wolf (Macmillan’s Standard Library), New York, N.Y.: Grosset & Dunlap, →OCLC

   Try to teach your child that there's a time to intervene and a time to mind your own business. Nobody loves a telltale.

   2011, Elizabeth Grahamslaw, A Parents' Guide To Primary School

   Synonyms: blabbermouth, gossip, rumormonger, squealer, talebearer, tattletale, carrytale, blab

2. An indicator, such as a warning light, that serves to warn of a hazard or problem.

   Except for informational readout displays, each discrete and distinct telltale shall be of the color shown in column 2 of Table 2.

   1980, The Code of Federal Regulations of the United States of America, page 150

   4 more examples

   A railroad company, which has properly erected a “telltale,” or signal board, to give warning of the approach of a train to a bridge and which lights the place at night by an electric light, is not responsible for injury caused at night by the “telltale” to a brakeman who had been passing under it at regular intervals for five weeks, though when injured he was standing upon a new car higher than those before used, and though he ad received no warning from the company as to the danger of standing upon such a car while passing under the "telltale".

   1893, “Case No. 2: Phillips vs. The Railroad Co.”, in The Counsellor: The New York Law School Law Journal, page 63

   A float telltale to be provided which shall connect with indicator on first floor by a small chain run through 1-2 inch pipe and over pulleys well guarded against the weather.

   1901, National Fire Protection Association, Proceedings - Volume 5, page 127

   For example, when trailers containing new automobiles were first piggybacked two areas of potential damage became evident: (1) diesel locomotive exhaust left a film of oil on the new autos; and (2) auto windshields could be scarred or cracked by the metal-tipped "tell-tales" which warn men atop trains of oncoming bridges or tunnels. Accordingly, automobiles aboard piggyback flats are usually coupled into the train 15 or more cars behind the locomotive; and telltales have been raised.

   1960 November, David Morgan, “"Piggyback"—U.S. success story”, in Trains Illustrated, page 684

   In order to resolve the discrepancy and permit the use of telltales in informational readout displays, the agency proposed the following requirement: Telltales and gauges incorporated into informational readout displays ( a ) Shall have not less than two levels of light intensity, a higher one for day and a lower one for nighttime conditions. (b) In the case of telltales amd gauges not equipped with a variable light intensity control shall have a light intensity at the higher level […]

   1994, United States. National Highway Traffic Safety Administration, Federal Motor Vehicle Safety Standards and Regulations, page 26

3. figurativelySomething that serves to reveal something else.

   The telltale was the lipstick on his shirt collar.

   4 more examples

   It supplies many useful links and tell-tales.

   1898, George Saintsbury, A Short History of English Literature

   In most cases the event is shielded by a large mass and only telltales arrive on earth. Such telltales include neutrinos, or even some form of radiation.

   2000, Dany Page, Jorge G. Hirsch, From the Sun to the Great Attractor, page 49

   It can be claimed that VC-dimension is to PAC-learning what finite telltales are to Inductive inference.

   2003, Eric Martin, Arun Sharma, Frank Stephan, “On Ordinal VC-Dimension and Some Notions of Complexity”, in Ricard Gavalda, Klaus P. Jantke, Eiji Takimoto, editors, Algorithmic Learning Theory, page 54

   Just as small pieces of rock produce telltale directional noon holes, so do large pieces of rock on snow produce telltales: but these telltales are of rather a different kind.

   2013, Harold Gatty, Finding Your Way Without Map or Compass

In a sentence

Your husband is at hand; I heare his Trumpet, / We are not tell-tales, Madam; feare you not.

c. 1596–1598 (date written), William Shakespeare, “The Merchant of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act V, scene i], page 183

Where it comes from

1. Middle Englishtale tellere
2. Englishtelltale

From tell + tale, perhaps dissimilated from earlier taleteller, from Middle English tale tellere (literally “tale teller”).