View source for Gnomon

{{also|gnómon}}
==English==
{{was wotd|2019|May|19}}

===Etymology===
{{multiple images
|direction = vertical
|image1 = Старые солнечные часы - panoramio (1).jpg
|caption1 = The gnomon ''(sense 1)'' of this [[sundial]] in {{w|Taganrog}}, [[w:Rostov|Rostov Oblast]], [[Russia]], is [[shape#Verb|shaped]] like a [[triangular]] [[blade]]
|image2 = Gnomon.svg
|caption2 = A gnomon in [[geometry]] ''(sense 4)''
|image3 = Square number 9 with gnomon.svg
|caption3 = [[four|Four]] is a [[figurate number]] as it can be represented by four dots arranged in a [[square#Noun|square]]. The next highest square is [[nine]]. Thus, the gnomon ''(sense 5)'' between four and nine is [[five]] ''(represented by the blue dots)''.
}}

{{root|en|ine-pro|*ǵneh₃-}}
Borrowed from {{bor|en|fr|gnomon}}, or directly from its {{glossary|etymon}} {{bor|en|la|gnōmōn}}, or directly from its etymon {{der|en|grc|γνώμων|t=discerner, interpreter; carpenter’s square; gnomon of a sundial; (''geometry'') gnomon}}, from {{m|grc|γιγνώσκω|t=to be aware of; to perceive; to know}}, ultimately from {{der|en|ine-pro|*ǵneh₃-|t=to know}}; the word is thus related to {{m|en|know}}.

The geometry sense ''(sense 4)'' is from the resemblance of the plane figure to a [[carpenter's square|carpenter’s square]].<ref>{{R:OED Online|part of speech=n|id=79523|date=1900}}</ref> Similarly, a gnomon in mathematics ''(sense 5)'' is also shaped like a carpenter’s square when [[depict]]ed [[pictorially]] if the [[figurate numbers]] are [[square#Noun|squares]].

===Pronunciation===
* {{IPA|en|/ˈnəʊˌmɒn/|/ˈnəʊ.mən/|a=RP}}
** {{audio|en|LL-Q1860 (eng)-Vealhurl-gnomon.wav|a=Southern England}}
* {{IPA|en|/ˈnoʊˌmɑn/|/ˈnoʊ.mən/|a=GA}}
* {{rhymes|en|əʊmɒn|əʊmən|oʊmɑn|oʊmən|s=2}}
* {{hyphenation|en|gno|mon}}

===Noun===
{{en-noun}}

# An [[object#Noun|object]] such as a [[pillar]] or a [[rod]] that is used to [[tell#Verb|tell]] [[time#Noun|time]] by the [[shadow#Noun|shadow]] it [[cast#Verb|casts]] when the [[sun#Noun|sun]] [[shine#Verb|shines]] on it, especially the [[pointer]] on a [[sundial]]. {{defdate|from mid 16th c.}}
#: {{synonyms|en|cock|style}}
#* {{quote-book|en|author=w:Samuel Foster|compiler=w:William Leybourn|chapter=[Projective Dialling: [...] The Ninth Tractate. Appendix.] Chap. IV. A General and Most Easie Way to Project Hour-lines upon All Kinds of Superfices without any Regard had to Their Standing, either in respect of Declination or Inclination|title=Dialling, Plain, Concave, Convex, Projective, Reflective, Refractive. Shewing, how to Make All such Dials, and to Adorn Them with All Useful Furniture Relating to the Course of the Sun;{{nb...|Performed Arithmetically, Geometrically, Instrumentally and Mechanically: And Illustrated with Sculptures Engraven in Copper. Comprised in XIV. Distinct Tractates, the Contents whereof Follow Next after the Preface to the Reader. The Second Edition Corrected, and Two New Tractates Added.}}|edition=2nd|location=London|publisher=Printed by J. Matthews, for [[w:Awnsham Churchill|Awnsham]] and John Churchill{{nb...|at the Black Swan in Pater-Noster-Row.}}|year=1700|page=83|pageurl=https://books.google.com/books?id=SUHWRGsPmS0C&pg=PA83|oclc=316646019|passage=Let a '''Gnomon''', being firſt ſharpened into a Point, be ſhaped, and faſtned in ſuch wiſe, that it no way hinder either the draught of the Horizontal Line, or the Point of the ſhadow from having free access to the Dial at all times of the Year. {{...}} Upon the Superfices of the Dial, obſerve the Point of the Shadow of the '''Gnomon''' (making a mark at it) and the Sun's Altitude, both of them at the ſame inſtant of time.}}
#* {{quote-journal|en|title=An Account of an Ancient Astronomical Instrument, of Immense Dimensions, lately Restored to Use|editor=Sylvanus Urban [pseudonym; {{w|Edward Cave}}]|magazine=[[w:The Gentleman's Magazine|The Gentleman’s Magazine, and Historical Chronicle]]|location=London|publisher=Printed by D[avid] Henry and R. Cave,{{nb...|at St John's Gate}}|month=March|year=1758|year_published=January 1755|volume=XXVIII|page=99|pageurl=https://books.google.com/books?id=DGHPAAAAMAAJ&pg=PA99|column=1|oclc=192374019|passage=The moſt celebrated '''gnomons''', for examining the courſe of the ſun, which are exiſting at this time, have been ſuppoſed to be that in the church of St ''Petronio'' at ''Bologna'', 89 ''Engliſh'' feet high; that of the ''Chartreux'' at ''Rome'', about 67 feet; and that of St ''Sulpice'' at ''Paris'', 86 feet. {{...}} [T]he '''gnomon''' of the cathedral of that city [Florence], erected by [[w:Paolo dal Pozzo Toscanelli|[''Paolo dal Pozzo''] ''Toscanelli'']], in the courſe of the 16th century, whoſe height exceeds that of the three before-mentioned, taken all together, being near 300 ''Engliſh'' feet, and higher than our ''London'' monument by almoſt a third part.}}
#* {{quote-book|en|author=Brahmegupta [''i.e.'', {{w|Brahmagupta}}]; Bháscara [''i.e.'', {{w|Bhāskara I}}]|chapter=Shadow of a Gnomon|translator=w:Henry Thomas Colebrooke|title=Algebra, with Arithmetic and Mensuration, from the Sanscrit of Brahmegupta and Bháscara|location=London|publisher=[[w:John Murray (publisher)|John Murray]],{{nb...|Albemarle Street.}}|year=1817|page=108|pageurl=https://books.google.com/books?id=ebZIAAAAcAAJ&pg=PA108|oclc=1038133983|passage=[T]he '''gnomon''' being the upright, and the shadow the side, the square-root of the sum of the squares is the hypotenuse; {{...}}}}
#* {{quote-book|en|author=R. M. Batson; V. S. Reed; R. L. Tyner|chapter=Cartographic Procedures|editors=[[w:George Ulrich (American geologist)|George E. Ulrich]], Carroll Ann Hodges, and [[w:William R. Muehlberger|William R[udolf] Muehlberger]]|title=Geology of the Apollo 16 Area, Central Lunar Highlands{{nb...|Prepared on Behalf of the National Aeronautics and Space Administration}}|series=[[w:United States Geological Survey|Geological Survey]] Professional Paper|seriesvolume=1048|location=Washington, D.C.|publisher=[[w:United States Government Publishing Office|United States Government Printing Office]]|year=1981|page=530|pageurl=https://books.google.com/books?id=tiksAQAAIAAJ&pg=PA530|oclc=6816255|passage=Approximate scales can be placed on near-field objects in pictures containing the '''gnomon''' by using an ellipse template. The {{w|Apollo 16}} '''gnomon''' {{...}} stands on three legs that, on a hard surface, define a circle 61.7 cm in diameter.}}
# An object such as a pillar used by an [[observer]] to [[calculate]] the [[meridian]] [[altitude]] of the sun (that is, the altitude of the sun when it [[reach#Verb|reaches]] the observer's meridian), for the purpose of [[determine|determining]] the observer's [[latitude]].
#* {{quote-book|en|author=w:Joseph Moxon|chapter=Prob[lem] XVIII. Another Way to Find the Height of the Pole by the Globe; if the Place of the Sun be Given; and also to Find the Hour of the Day, and Azimuth, and Almicantar of the Sun.|title=A Tutor to Astronomie and Geographie: Or An Easie and Speedy Way to Know the Use of Both the Globes, Cœlestial and Terrestrial. In Six Books.{{nb...|The First Teaching the Rudiments of Astronomy and Geography. The 2. 3. 4. 5. 6. Shewing by the Globes the Solution of Astronomical & Geographical Probl. Problemes in Navigation. Astrological Problemes. Gnomonical Problemes. Of Spherical Triangles. More Fully and Amply then hath ever been Set forth either by Gemma Frisius, Metius, Hues, Wright, Blaew, or any Others that have Taught the Use of the Globes: And that so Plainly and Methodically that the Meanest Capacity may at First Reading Apprehend It; and with a Little Practise Grow Expert in These Divine Sciences. By Joseph Moxon. Whereunto is Added the Antient Poetical Stories of the Stars: Shewing Reasons why the Several Shapes and Forms are Pictured on the Cœlestial globe. Collected from Dr. Hood. As also a Discourse of the Antiquity, Progress and Augmentation of Astronomie.}}|location=London|publisher=Printed by Joseph Moxon;{{nb...|and sold at his shop on Corn-hill, at the signe of Atlas.}}|year=1659|section=2nd book (Shewing the Practical Use of the Globes. Applying Them to the Solution of Astronomical and Geographical Problemes.)|page=56|pageurl=https://books.google.com/books?id=dKFkAAAAcAAJ&pg=PA56|oclc=228725173|passage=This muſt be performed by help of a ''Spherick '''Gnomon''''', (as ''Blaew'' &#91;[[w:Willem Blaeu|Willem Janszoon Blaeu]]&#93; calls it,) which is a ſmall Pin or Needle fixed perpendicularly into a ſmal Baſis with an hollow concave bottom, that it may ſtand upon the convexity of the Globe.}}
#* {{quote-book|en|author=[[w:William Robertson (historian)|William Robertson]]|chapter=Section II. Intercourse with India, from the Establishment of the Roman Dominion in Egypt, to the Conquest of that Kingdom by the Mahomedans|title=An Historical Disquisition Concerning the Knowledge which the Ancients had of India;{{nb...|and the Progress of Trade with that Country, prior to the Discovery of the Passage to It by the Cape of Good Hope. With an Appendix, Containing Observations on the Civil Policy—the Laws and Judicial Proceedings—the Arts—the Sciences—and the Religious Institutions, of the Indians.}}|location=London|publisher=Printed for [[w:Andrew Strahan|A[ndrew] Strahan]], and [[w:Thomas Cadell (publisher)|T[homas] Cadell]]{{nb...|in the Strand}}; Edinburgh: E. Balfour|year=1791|pages=78–79|pageurl=https://books.google.com/books?id=xcERAAAAYAAJ&pg=PA78|oclc=1035338177|passage=In order to aſcertain the latitude of any place, the ancients obſerved the meridian altitude of the ſun, either by means of the ſhadow of a perpendicular '''gnomon''', or by means of an aſtrolabe, from which it was eaſy to compute how many degrees and minutes the place of obſervation was diſtant from the Equator.}}
# The [[index#Noun|index]] of the [[hour circle]] of a [[globe]].
#* {{RQ:British Encyclopedia|volume=III|entry={{smallcaps|Index}} ''of a globe''|noformat=yes|url=https://archive.org/details/gri_33125014817791/page/n619/mode/1up|column=2|passage={{smallcaps|Index}} ''of a globe'', the little style or '''gnomon''', which being fixed on the pole of the globe, and turning round with it, points out the hours upon the hour circle.}}
# {{lb|en|geometry}} A [[plane#Adjective|plane]] [[figure#Noun|figure]] [[form#Verb|formed]] by [[remove#Verb|removing]] a [[parallelogram]] from a [[corner#Noun|corner]] of a larger parallelogram.
#* {{RQ:Chambers Cyclopaedia|entry=Gnomon|page=164|pageurl=https://archive.org/stream/gri_33125011113764#page/n915/mode/1up|column=2|passage=If a Parallelogram be divided into four leſſer ones, by two Lines interſecting each other; and one of theſe Parallelograms be retrench'd, or taken away; the other three will make a '''''Gnomon''''', ordinarily call'd a ''Square''.}}
# {{lb|en|mathematics|by extension}} A [[number#Noun|number]] [[represent]]ing the [[increment#Noun|increment]] between two {{l|en|figurate number|figurate numbers|numbers [[equal#Adjective|equal]] to the numbers of [[dot#Noun|dots]] in [[geometric]] figures formed of dots}}.
#* {{quote-book|en|author=w:Midhat J. Gazalé|chapter=Figurate and <math>m</math>-adic Numbers|title=Gnomon: From Pharaohs to Fractals|location=Princeton, N.J.; Chichester, West Sussex|publisher=w:Princeton University Press|year=1999|pages=16 and 17|pageurl=https://books.google.com/books?id=R0d76m-Be10C&pg=PA16|isbn=978-0-691-00514-0|passage=&#91;[https://books.google.com/books?id=R0d76m-Be10C&pg=PA16 page 16]&#93; The figurate number's '''gnomon''' is therefore <math>1+nb</math> in the general case. A trivial family of numbers, those for which <math>b=0</math>, might be called ''linear''. {{...}} &#91;[https://books.google.com/books?id=R0d76m-Be10C&pg=PA17 page 17]&#93; Clearly, a figurate number of rank <math>n</math> is equal to the sum of its first <math>n</math> '''gnomons''', and in particular ''the sum of the first'' <math>n</math> ''odd numbers is equal to'' <math>n^2</math>.}}

====Related terms====
{{col|en
|gnomonic
|gnomonics
|gnomonist
}}

====Translations====
{{trans-top|object used to tell time by the shadow it casts when the sun shines on it}}
* Arabic: {{t|ar|قياس|m|tr=qiyās}}
* Armenian: {{t|hy|գնոմոն}}
* Basque: {{t|eu|gnomon}}
* Belarusian: {{t|be|гно́ман|?}}
* Bulgarian: {{t|bg|гно́мон|m}}
* Catalan: {{t|ca|gnòmon|m}}, {{t+|ca|estil|m}}
* Chinese:
*: Mandarin: {{t|cmn|晷針|tr=guǐzhēn}}
* Czech: {{t|cs|gnómon|m}}
* Danish: {{t-needed|da}}
* Dutch: {{t+|nl|gnomon|m}}
* Estonian: {{t|et|gnoomon}}
* Finnish: {{t+|fi|gnomon}}
* French: {{t+|fr|gnomon|m}}, {{t+|fr|style|m}}
* Friulian: {{t|fur|gnomon|m}}, {{t|fur|aste|f}}
* Galician: {{t|gl|gnomon|m}}
* Georgian: {{t|ka|გნომონი}}
* German: {{t+|de|Gnomon|m}}
* Greek: {{t+|el|γνώμονας|m}}
*: Ancient: {{t|grc|γνώμων|m}}, {{t|grc|κερκίς|m}}
* Hebrew: {{t|he|גנומון|?}}
* Hindi: {{t+|hi|शंकुक|?}}
* Hungarian: {{t|hu|gnómon}}
* Icelandic: {{t|is|sólsproti|?}}
* Ido: {{t+|io|gnomono}}
* Irish: {{t|ga|snáthaid|f}}, {{t|ga|snáthaid chlog gréine|f}}
* Italian: {{t+|it|gnomone|m}}, {{t+|it|stilo|m}}
* Japanese: {{t|ja|グノモン}}
* Korean: {{t|ko|규표(圭表)}}
* Latvian: {{t|lv|gnomons|m}}
* Lithuanian: {{t|lt|gnomonas|m}}
* Malay: {{t|ms|paku bayang}}
* Norwegian:
*: Bokmål: {{t|nb|gnomon|m}}
* Occitan: {{t|oc|gnomòn|m}}
* Persian: {{t|fa|اشاره‌گر}}, {{t+|fa|شاخص|tr=šâxes}}
* Polish: {{t+|pl|gnomon|m}}
* Portuguese: {{t|pt|gnômon|m}}
* Russian: {{t+|ru|гно́мон|m}}
* Sanskrit: {{t+|sa|नृ|m}}, {{t+|sa|स्थाणु|m}}
* Serbo-Croatian:
*: Cyrillic: {{t|sh|гно̀мо̄н|m}}
*: Roman: {{t+|sh|gnòmōn|m}}
* Slovak: {{t|sk|gnómon|m}}
* Slovene: {{t|sl|gnómon|?}}
* Spanish: {{t+|es|estilo|m}}
* Swedish: {{t|sv|gnomon|?}}
* Turkish: {{t|tr|gnomon}}
* Ukrainian: {{t|uk|ґно́мон|?}}
{{trans-bottom}}

{{trans-top|object used to calculate the meridian altitude of the sun}}
* Friulian: {{t|fur|gnomon|m}}
* Romanian: {{t+|ro|gnomon|n}}
{{trans-bottom}}

{{trans-top|index of the hour circle of a globe}}
{{trans-bottom}}

{{trans-top|plane figure formed by removing a parallelogram from a corner of a larger parallelogram}}
* French: {{t+|fr|gnomon|m}}
* Friulian: {{t|fur|gnomon|m}}
* Hungarian: {{t|hu|gnómon}}
* Slovene: {{t|sl|gnomon|?}}
* Urdu: {{t+|ur|علم|m}}
{{trans-bottom}}

{{trans-top|number representing the increment between two figurate numbers}}
{{trans-bottom}}

===References===
<references />

===Further reading===
* {{pedia}}
* {{pedia|gnomon (figure)}}
* {{pedia|gnomon (disambiguation)}}
* {{R:Century 1911}}
* {{R:Webster 1913}}
* {{R:OneLook}}
* {{R:Lexico}}

{{C|en|Clocks|Timekeeping}}

==Dutch==

===Pronunciation===
* {{audio|nl|Nl-gnomon.ogg}}
{{rfp|nl}}

===Noun===
{{nl-noun|m|-s|-}}

# {{l|en|gnomon}}

====Related terms====
{{col|nl|zonnewijzer}}

===Further reading===
* {{R:GB}}

==Esperanto==

===Pronunciation===
{{eo-IPA}}

===Noun===
{{eo-head}}

# {{eo-form of|gnom|on}}

==French==

===Etymology===
{{bor+|fr|la|gnōmōn}}, from {{der|fr|grc|γνώμων|t=indicator}}.

===Pronunciation===
* {{fr-IPA|g_nomon}}
* {{audio|fr|LL-Q150 (fra)-LoquaxFR-gnomon.wav}}

===Noun===
{{head|fr|noun}}

# [[#English|gnomon]]

====Related terms====
{{col|fr|gnomonique}}

===Further reading===
* {{R:fr:TLFi}}

{{C|fr|Clocks}}

==Latin==
[[File:Museum side roman sun dial 2.JPG|thumb|gnōmōn (rod on a sundial)]]

===Etymology===
{{bor+|la|grc|γνώμων|t=discerner, interpreter; gnomon of a sundial}}, from {{m|grc|γιγνώσκω|t=to be aware of; to perceive; to know}}, ultimately from {{der|la|ine-pro|*ǵneh₃-|t=to know}}.

===Pronunciation===
* {{la-IPA|gnōmōn|eccl=yes}}

===Noun===
{{la-noun|gnōmōn/gnōmon<3>|g=m}}

# [[#English|gnomon]]; rod or pillar on a [[sundial]] whose shadow is used to indicate the [[time]]

====Declension====
{{la-ndecl|gnōmōn/gnōmon<3.-N>}}

====Derived terms====
{{col|la
|gnōmonicē
|gnōmonicus
}}

====Descendants====
; All borrowed
{{top3}}
* {{desc|ca|gnòmon}}
* {{desc|en|gnomon}}
* {{desc|fr|gnomon}}
* {{desc|it|gnomone}}
* {{desc|pt|gnômon}}
* {{desc|ro|gnomon}}
* {{desc|es|gnomon}}
{{bottom}}

===References===
* {{R:L&S}}
* {{R:Gaffiot}}

==Polish==

===Pronunciation===
{{pl-pr|a=LL-Q809 (pol)-Olaf-gnomon.wav}}

===Noun===
{{pl-noun|m-in}}

# [[#English|gnomon]]

====Declension====
{{pl-decl-noun-masc-inani}}

====Related terms====
{{col|pl|title=adjective|gnomoniczny}}
{{col|pl|title=noun|gnomonika}}

===Further reading===
* {{R:pl:WSJP}}
* {{R:pl:PWN}}

==Romanian==

===Etymology===
{{bor+|ro|fr|gnomon}} or {{bor|ro|la|gnomon}}.

===Pronunciation===
* {{IPA|ro|/ɡnoˈmon/}}

===Noun===
{{ro-noun|n|gnomoane}}

# [[#English|gnomon]]

====Declension====
{{ro-noun-n|pl=gnomoane}}

====Related terms====
{{col|ro
|gnomonic
|gnomonică
}}

===Further reading===
* {{R:DEX}}

==Swedish==

===Pronunciation===
{{rfp|sv}}

===Noun===
{{sv-noun}}

# {{l|en|gnomon}}

====Declension====
{{rfinfl|sv|noun}}

====Related terms====
{{col|sv
|gnomonik
|gnomonisk
}}

===Further reading===
* {{R:sv:SO}}