Pentad — Pen tad, n. [Gr. ?, ?, a body of five, fr. ? five.] (Chem.) Any element, atom, or radical, having a valence of five, or which can be combined with, substituted for, or compared with, five atoms of hydrogen or other monad; as, nitrogen is a pentad … The Collaborative International Dictionary of English
Pentad — Pen tad, a. (Chem.) Having the valence of a pentad. [1913 Webster] … The Collaborative International Dictionary of English
pentad — 1650s, from Gk. pentas, pentada “group of five” (see FIVE (Cf. five)). Meaning “period of five years” is from 1880; meaning “period of five days” is from 1906, originally in meteorology … Etymology dictionary
pentad — [pen′tad΄] n. [Gr pentas (gen. pentados) < pente,FIVE] 1. the number five 2. a series or group of five 3. a five year period 4. Chem. a pentavalent element or radical … English World dictionary
pentad — noun Etymology: Greek pentad , pentas, from pente Date: 1653 a group of five … New Collegiate Dictionary
pentad — /pen tad/, n. 1. a period of five years. 2. a group of five. 3. the number five. 4. Chem. a pentavalent element or group. 5. Climatol. a period of five consecutive days. [1645 55; < Gk pentad (s. of pentás) group of five. See PENT , AD1] * * * … Universalium
pentad — [ pɛntad] noun a group or set of five. Origin C17: from Gk pentas, pentad , from pente five … English new terms dictionary
pentad — pen•tad [[t]ˈpɛn tæd[/t]] n. 1) a period of five years 2) math. a group of five 3) the number five 4) chem. a pentavalent element or group • Etymology: 1645–55; < Gk pentad (s. of pentás) group of five. See pent , ad I … From formal English to slang
pentad — /ˈpɛntæd/ (say pentad) noun 1. a period of five years. 2. Meteorology a period of five days. 3. a group of five. 4. the number five. 5. Chemistry Obsolete a pentavalent element or group. {Greek pentas a group of five} …
Pentad (Greek philosophy) — The pentad was a Pythagorean term for the number five. A pentagram, symbol of the pentad, was used by the as a secret sign to recognize each other.cite book |author=Ghyka, Matila C. |title=The geometry of art and life |publisher=Dover… … Wikipedia
pentad — noun a group or series of five things … Wiktionary
