The noun is borrowed fromFrenchsémaphore, fromAncient Greekσῆμα(sêma,“mark, sign, token”) +French-phore (fromAncient Greek-φόρος(-phóros,suffix indicating a bearer or carrier)).[1] Bysurface analysis,sema- +-phore.
The verb is derived from the noun.[2]
semaphore (countable anduncountable,pluralsemaphores)
- Anyequipmentused forvisualsignalling by means offlags,lights, ormechanicallymovingarms, which are used torepresentletters of thealphabet, orwords.
[1820 January, “Art. II.—Thesaurus Græcæ Linguæ ab H. Stephano[Henry Stephens]constructus. Editio nova, auctior et emendatior. Vol. I. Partes I–IV. Londini, in ædibus Valpianis, 1815–1818.[book review]”, inWilliam Gifford, editor,The Quarterly Review, volume XXII, number XLIV, London:John Murray, […],→OCLC,page342:We must here take the liberty of expostulating with SirHome [Riggs] Popham and the first Lord of the Admiralty, for having given to the telegraphic machine, invented by that gallant officer, the barbarous name ofSemaphore, instead ofSematophore orSemophore—either of them ugly enough.]
1821, “[Papers in Mechanics.] No. V. Improved Semaphore.”, inTransactions of the Society, Instituted at London, for the Encouragement of Arts, Manufactures, and Commerce; […], volume XXXIX, London: Sold by the housekeeper, at the Society’s House, […]; printed byT[homas] C[urson] Hansard, […],→OCLC,page104:The largeSilver Medal of the Society was this Session voted toNic[h]olas Harris Nicolas, Esq. of the Inner Temple, for an Improvement on theVerticalSemaphore, and for his method of adapting a shifting Key to Telegraphic Communications, for the purpose of insuring their Secrecy. A Model of Mr. N'sSemaphore has been placed in the Repository of the Society.
1831 October 8, W. Thomas, “[General Correspondence.] Night Signals.”, inThe United Service Journal, and Naval and Military Magazine, part III, number35, London:Henry Colburn andRichard Bentley, […],→OCLC,page392:That the systems of telegraph andsemaphore now in use are in a great measure use-less by night, and totally so in a fog, cannot be doubted; and that a mode, both rapid and secret, would could be put into practice at small expense, in fact little more than the first cost, would be of essential utility to the Government of the country adopting it, is equally true.
1879,Albert J[ames] Myer, “Semaphores”, inA Manual of Signals for the Use of Signal Officers in the Field, […], Washington, D.C.:Government Printing Office,→OCLC,pages193–194:When, on long lines of stations, towers or other structures are used, it may be necessary, for greater speed, to sometimes employsemaphores for aerial telegraphy. [...]Semaphores consist of a post with arms. The arms starting with about three feet in length, to be increased one foot for every mile. These arms are made movable by ropes passing over wheels or pulleys, and moved by a crank below.
1895 January–June,Rudyard Kipling, “An Unqualified Pilot”, inLand & Sea Tales for Scouts and Guides, Bombay: The Gresham Publishing Company; London:Macmillan and Co., published August 1919,→OCLC,page68:And so they went down, Jim steering by his father, turn for turn, over the Mayapur Bar, with thesemaphores on each bank duly signalling the depth of water, [...]
1906 July 19, “The Wright Telegraph Railroad Signal”, inThe Iron Age, volume LXXVIII, New York, N.Y.: David Williams Company […],→OCLC,page139, column 2:It is essentially an emergency device, primarily for use on single track railroads, and is intended to place the control ofsemaphores at the several stations under the control of the dispatcher. By means of this signal the dispatcher may throw asemaphore to "stop position" at any desired point, regardless of the condition of the operator's instrument at that station, that is whether or not the key of his instrument on the dispatcher's wire is open.
1941 April, “Centenary of theSemaphore Signal”, inRailway Magazine, page171:Now, a century later,semaphores and discs are giving place to colour and position lights. What will be the fashion in 2041? Universal continuous cab signalling?
1968, F[rits] van der Gragt,Europe's Greatest Tramway Network: Tramways in the Rhein–Ruhr Area of Germany (Uitgaven van de Nederlandsche Vereeniging van Belangstellenden in het Spoor- en Tramwegwezen[Publications by the Dutch Association of People Interested in the Rail- and Tramway System]; 4), Leiden:E[vert] J[an] Brill,→OCLC,page128:Travelling by the rural tramway was quite an experience; the small car would bounce about on the bad track like a ship in a rough sea; at some places, there would even be genuine railwaysemaphore signals controlling the trams.
1995, Sten Thore, “Messages, Images, and Robots”, inThe Diversity, Complexity, and Evolution of High Tech Capitalism, Boston, Mass.; Dordrecht:Kluwer Academic Publishers,→ISBN,page27:Innovations in the communications industry often means that existing media become obsolete. There are nosemaphores any longer. (Semaphores were used by the French revolutionary armies in the late 1790's to relay information to Paris about their victories in the Savoy.)
2020 December 2, Paul Bigland, “My weirdest and wackiest Rover yet”, inRail, page67:Even so, there are only four others in my car after leaving the pretty station atAbergavenny, a haven of old GWRsemaphores.
- A visualsystem fortransmittinginformation using the above equipment; especially, by means oftwo flags heldone in eachhand, using analphabetic andnumericcodebased on theposition of thesignaller's arms;flag semaphore.
1834 October, Charles Blackburn, “XXXV. A Method of Determining the Number of Signals which Can be Made by the Modern Telegraphs.”, inDavid Brewster,Richard Taylor,Richard Phillips, editors,The London and Edinburgh Philosophical Magazine and Journal of Science, volume V (Third Series), number28, London: Printed by Richard Taylor, […], printer to theUniversity of London; sold byLongman, Rees, Orme, Brown, Green, and Longman;[et al.],→OCLC,page241:Its [the article's] object is to furnish a rule for determining the number of distinct signals which can be made by anysemaphore, whatever be the number of arms or indicators, of whatever be the number of positions of each arm. In the Cyclopædia of Rees, the number of signals which thesemaphores of the line of communication between Paris and Landau were capable of making, is stated to be 823,543, which is no less than 1,274,608 fewer than the real number, an error not arising from the press, but from the principle of computation.
1924 September, Arthur Conan Doyle, “Sidelights on Sherlock Holmes”, inMemories and Adventures, Boston, Mass.:Little, Brown, and Company,→OCLC,page110:Buried treasures are naturally among the problems which have come to Mr.[Sherlock] Holmes. One genuine case was accompanied by a diagram here reproduced. [...] EachIndiaman in those days had its ownsemaphore code, and it is conjectured that the three marks upon the left are signals from a three-armedsemaphore.
2006, Erinn Banting,Inventing the Telephone (Breakthrough Inventions), New York, N.Y.; Toronto, Ont.: Crabtree Publishing Company,→ISBN,page 5, column 2:A system of communication calledsemaphore uses flags or flashing lights to send messages over distances. [...] Code flags are less common today but are sometimes used by ships that have lost radio contact.
2010, Jonathan Balcombe, “Communicating”, inSecond Nature: The Inner Lives of Animals, New York, N.Y.:St. Martin’s Press,→ISBN, part II (Coexistence),page84:Semaphore—a system of communicating over long distances by holding the arms or two flags in certain positions—is not a very efficient mode of communication for us. But for the Panamanian golden frog,semaphore is just the ticket. These frogs live near waterfalls, where the constant din renders vocal communication useless. [...] When they want to get someone else's attention, they flash pale patches of skin on their limbs or the webs between their toes.
2014, Bernard F. Dick, “Worlds Elsewhere”, inThe President’s Ladies:Jane Wyman andNancy Davis, Jackson, Miss.:University Press of Mississippi,→ISBN,page215:For a half-hour episode, "The Long Shadow" was unusually complex, a web spun out of deception and equivocation that untangles when[Ronald] Reagan, transmitting his customizedsemaphores of concern (ridged brow, pursed lips, pained eyes), divulges the truth: [...]
- (programming) Abit,token,fragment of code, or some othermechanism which is used torestrictaccess to asharedfunction ordevice to asingleprocess at atime, or tosynchronize andcoordinateevents indifferent processes.
The thread increments thesemaphore to prevent other threads from entering thecritical section at the same time.
1996, P. Theodoropoulos, G. Manis, P. Tsanakas, G. Papakonstantinou, “Extending Synchronization PVM Mechanisms”, in Arndt Bode,Jack Dongarra, Thomas Ludwig, Vaidy Sunderam, editors,Parallel Virtual Machine – EuroPVM ’96: Third European PVM Conference, Munich, Germany, October 7–9, 1996: Proceedings (Lecture Notes in Computer Science;1156), Berlin; Heidelberg:Springer-Verlag,→ISBN,→ISSN,page315:Several synchronization techniques have been proposed and many of them have been adopted by parallel and distributed operating systems or parallel programming platforms. [...]Semaphores represent another synchronization technique that is mainly used by traditional stand-alone operating systems.
2003, David Sklar, Adam Trachtenberg, “Variables”, in Paula Ferguson, editor,PHP Cookbook, Sebastopol, Calif.:O’Reilly & Associates,→ISBN, section 5.6 (Sharing Variables across Processes),page124:Asemaphore makes sure that the different processes don't step on each other's toes when they access the shared memory segment. Before a process can use the segment, it needs to get control of thesemaphore. When it's done with the segment, it releases thesemaphore for another process to grab.
2012, Timothy Mangan, “L1/L2/L3 Memory Cache”, inWindows System Performance through Caching: 15 Ways Caching Improves System Performance (Inside the OS Series), Canton, Mass.: TMurgent Technologies,→ISBN,page22:It is up to the programmer to ensure that if one thread updates multiple dependent memory locations (for example, writing a string, or updating a table) that another thread might read, some protection is put in place to ensure that the two threads don't update and read at the same time. [...] Several techniques are used by programmers to prevent this, including locks,semaphores, and mutexes.
equipment used for visual signalling
visual system for transmitting information
visual system for transmitting information using flags
mechanism used to restrict access to a shared function or device to a single process at a time
semaphore (third-person singular simple presentsemaphores,present participlesemaphoring,simple past and past participlesemaphored)
- (ambitransitive, figurative) Tosignal using, or as if using, a semaphore, with theimplication that it is donenonverbally.
1907,United States Hydrographic Office, “Distant Signals”, inInternational Code of Signals, American edition, Washington, D.C.:Government Printing Office,→OCLC, part III,page539:The person intending toSemaphore will make the International Code Signal VOX (I am going toSemaphore to you), and set his Semaphore at the alphabetical sign [...] with the Indicator out, and wait until the person to whom the Semaphore signal is to be made hoists his answering pennantclose up. [...] The British method ofSemaphoring by flags held in the hand which is shown in plate VIII is exactly the same as the British Movable Semaphore system, which has just been explained, the positions of the apparatus which denote the letters, numbers, and special signs being, it will be seen, identical in each case, and the only difference being in the apparatus employed.
1990,Peter Hopkirk, “The Climactic Years”, inThe Great Game: On Secret Service in High Asia, London:John Murray,→ISBN; republished Oxford, Oxfordshire:Oxford University Press,2001,→ISBN,page478:Minutes later, unseen by the defenders, hesemaphored back across the valley that he was going to make a fresh attempt.
2008, Elizabeth Elwood, “Gilda Died for Love”, inA Black Tie Affair: And Other Mystery Stories, Lincoln, Neb.:iUniverse,→ISBN,page113:Near the concession stand on the east side of the park, she saw two familiar figures sitting on a bench in the shade of a large oak. Her father hailed her, wildlysemaphoring with his hot dog.
2011, Heather Menzies Jones, chapter 25, inNanoMan,[Morrisville, N.C.]:Lulu.com,→ISBN,page133:He can't hear what they're saying, but Jake is making angry movements with his hands and his taut posturesemaphores, even to Daniel, his distinct displeasure.
2012 September,Ta-Nehisi Coates, “Fear of a Black President”, inJames Bennet, editor,The Atlantic[1], Washington, D.C.: The Atlantic Monthly Group,→ISSN,→OCLC, archived fromthe original on3 January 2020:[Barack] Obama doesn't merely evince blackness; he uses his blackness to signal and court African Americans,semaphoring in a cultural dialect of our creation—crooningAl Green at the Apollo, name-checkingYoung Jeezy, regularly appearing on the cover of black magazines, weighing the merits ofJay-Z versusKanye West, being photographed in the White House with a little black boy touching his hair.
to signal using, or as if using, a semaphore
- ^“semaphore,n.”, inOED Online
, Oxford:Oxford University Press, March 2014;“semaphore,n.”, inLexico,Dictionary.com;Oxford University Press,2019–2022. - ^“semaphore,v.”, inOED Online, Oxford:Oxford University Press, March 2014;“semaphore,v.”, inLexico,Dictionary.com;Oxford University Press,2019–2022.
, Oxford:Oxford University Press, March 2014;“semaphore,n.”, inLexico,Dictionary.com;Oxford University Press,2019–2022.
