pentad
nounUS /ˈpɛnˌtæd/ · UK /ˈpɛntad/
Etymology From Ancient Greek πεντάς (pentás), from πέντε (pénte, “five”) + -άς (-ás, “-ad”). By surface analysis, pent- + -ad.
› Synonym of quintet: A group of five things…
1
Synonym of quinquennium: a five-year period, especially in reference to the first and second halves of calendrical decades.
2
Climatology, Natural sciences A five-day period, especially a temperature average taken every five days.
3
A five-day division of the Chinese calendar, forming part of a solar term (Chinese: 候).
4
Chemistry, Natural sciences, Physical sciences 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.
- Derived terms
- pentadic, Reynolds' pentad