apex

Borrowed from Latin apex (“point, tip, summit”).

• IPA^(key): /ˈeɪ.pɛks/

• Audio (Southern England)

  (file)

• Rhymes: -eɪpɛks

apex (plural apices or apexes)

1. The highest or the greatest part of something, especially forming a point.

   the apex of the building

   Synonyms: peak, top, summit, vertex

   1. (geometry) The highest point in a plane or solid figure, relative to a base line or plane.
   2. (chiefly anatomy) The pointed fine end of something.

      Synonyms: end, tip

      1. The lowest part of the human heart.
         • 1951 March, J. H. Lehmann, A. D. Johnson, W. C. Bridges, J. Michel, D. M. Green, “Cardiac Catheterization—A Diagnostic Aid in Congenital Heart Disease”, in Northwest Medicine, volume 50, number 3, Portland, Ore.: Northwest Medical Publishing Association, page 175:

           B.P. 118/68. Grade I diastolic murmur best heard over apex. Patient well and had no complaints referable to heart. Origin of the diastolic murmur is open to conjecture.

      2. The deepest part of a tooth's root.
   3. (botany) The end of a leaf, petal or similar organ opposed to the end where it is attached to its support.

      Synonym: tip

   4. (botany) The growing point of a shoot.
   5. (astronomy) The point on the celestial sphere toward which the Sun appears to move relative to nearby stars.

      Hyponym: solar apex

   6. (physics) The lowest point on a pendant drop of a liquid.
   7. (mining, US) The end or edge of a vein nearest the surface.
   8. (typography):
      1. A diacritic in Classical Latin that resembles and gave rise to the acute.
      2. A diacritic in Middle Vietnamese that indicates /ŋ͡m/.
      3. A sharp upward point formed by two strokes that meet at an acute angle, as in "W", uppercase "A", and closed-top "4", or by a tapered stroke, as in lowercase "t".

         Coordinate term: vertex

2. (figuratively) The moment of greatest success, expansion, etc.

   the apex of civilization

   • 2002, Jeffrey Rowland, “Day 2 (The Slagathors)”, in Wigu Adventures‎, page 58:

     It would be an intense disgust. The absolute apex of teen angst.

   • 2008, BioWare, Mass Effect (Science Fiction), Redwood City: Electronic Arts, →ISBN, →OCLC, PC, scene: Virmire:

     The pattern has repeated itself more times than you can fathom. Organic civilizations rise, evolve, advance. And at the apex of their glory, they are extinguished.

   Synonyms: acme, culmination, height, peak, pinnacle

3. (attributive, ecology) The top of the food chain.
4. A conical priest cap.

• See also Thesaurus:apex

• apical

• “apex”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.
• “apex”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “apex”, in The Century Dictionary […], New York, N.Y.: The Century Co., 1911, →OCLC.
• “apex”, in OneLook Dictionary Search.

From Proto-Italic *apeks, from Proto-Indo-European *h₂ep- (“to join, fit”). Cognate with Latin apō (“to fasten, join, tie to”).

• (Classical) IPA^(key): /ˈa.peks/, [ˈäpɛks̠]
• (modern Italianate Ecclesiastical) IPA^(key): /ˈa.peks/, [ˈäːpeks]

apex m (genitive apicis); third declension

1. The extreme end of a thing; the point, summit, top.

   Synonyms: cacūmen, summa, fastīgium, culmen, vertex, summitās

   Antonym: fundus

2. (literally) The small rod (generally of olive wood) at the top of the flamen's cap, wound around with a woolen cord or "thread".
3. (transferred sense):
   1. The conical leathern cap of an ancient Roman priest (the Flamen), ornamented with this rod.
   2. Any hat or helmet; a crown.
   3. (literally) A projecting point or summit.
      1. (figurative) The highest ornament or honor; the crown of a thing.
   4. (grammar) The macron (long mark over a vowel).
      1. The forms or outlines of the letters.
   5. A letter or any other writing.
   6. (Ecclesiastical Latin, figurative) (of the point or apex of a Hebrew letter) The least particle, tittle.

Third-declension noun.

• “apex”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “apex”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• apex in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
• apex in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
• “apex”, in Harry Thurston Peck, editor (1898), Harper's Dictionary of Classical Antiquities, New York: Harper & Brothers
• “apex”, in William Smith et al., editor (1890), A Dictionary of Greek and Roman Antiquities, London: William Wayte. G. E. Marindin

Borrowed from Latin apex.

apex n (plural apexuri)

1. apex