pentad
English
Etymology
From Ancient Greek πεντάς (pentás), from πέντε (pénte, “five”) + -άς (-ás, “-ad”), equivalent to pent- + -ad.
Pronunciation
- (General American) IPA(key): /ˈpɛnˌtæd/
- (Received Pronunciation) IPA(key): /ˈpɛntad/
- Hyphenation: pen‧tad
Noun
pentad (plural pentads)
- Synonym of quintet: A group of five things, particularly
- Synonym of quinquennium: a five-year period, especially in reference to the first and second halves of calendrical decades.
- (climatology) A five-day period, especially a temperature average taken every five days.
- (chemistry) A pentavalent element or group: an atom or molecule with a valence of five, comparable with five atoms of hydrogen.
- Nitrogen is a pentad in the ammonium compounds.
Coordinate terms
- (group) monad, duad/dyad, triad, tetrad, pentad, hexad, hebdomad/heptad, ogdoad/octad, ennead/nonad, decad/decade, hendecad, dodecad/duodecade, chiliad
Derived terms
- pentadic
References
- “pentad, n.”, in OED Online
, Oxford, Oxfordshire: Oxford University Press, 2022.
Anagrams
- panted, pedant