pentad

From Ancient Greek πεντάς (pentás), from πέντε (pénte, “five”) + -άς (-ás, “-ad”), equivalent to pent- +‎ -ad.

• (General American) IPA^(key): /ˈpɛnˌtæd/
• (Received Pronunciation) IPA^(key): /ˈpɛntad/
• Hyphenation: pen‧tad

pentad (plural pentads)

1. Synonym of quintet: A group of five things, particularly
   1. Synonym of quinquennium: a five-year period, especially in reference to the first and second halves of calendrical decades.
   2. (climatology) A five-day period, especially a temperature average taken every five days.
   3. An five-day division of the Chinese calendar, forming part of a solar term (Chinese: 候).
   4. (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.

• (group) monad, duad/dyad, triad, tetrad, pentad, hexad, hebdomad/heptad, ogdoad/octad, ennead/nonad, decad/decade, hendecad, dodecad/duodecade, chiliad

• pentadic

• “pentad, n.”, in OED Online ⁠, Oxford, Oxfordshire: Oxford University Press, 2022.

• panted, pedant

From French pintade.

pentad

1. guinea fowl
2. (figurative) shy and cowardly (person)

• pentadin