Source : Webster's Revised Unabridged Dictionary (1913)

Ethos \E"thos\, n. [L., fr. Gr. ? character. See {Ethic}.]
   1. The character, sentiment, or disposition of a community or
      people, considered as a natural endowment; the spirit
      which actuates manners and customs; also, the
      characteristic tone or genius of an institution or social
      organization.

   2. ([AE]sthetics) The traits in a work of art which express
      the ideal or typic character -- character as influenced by
      the ethos (sense 1) of a people -- rather than realistic
      or emotional situations or individual character in a
      narrow sense; -- opposed to {pathos}.

Source : WordNet®

ethos
     n : (anthropology) the distinctive spirit of a culture or an
         era; "the Greek ethos"