Source : Webster's Revised Unabridged Dictionary (1913)

Knighthood \Knight"hood\, n. [Knight + hood: cf. AS. chihth[=a]d
   youth.]
   1. The character, dignity, or condition of a knight, or of
      knights as a class; hence, chivalry. ``O shame to
      knighthood.'' --Shak.

            If you needs must write, write C[ae]sar's praise;
            You 'll gain at least a knighthood, or the bays.
                                                  --Pope.

   2. The whole body of knights.

            The knighthood nowadays are nothing like the
            knighthood of old time.               --Chapman.

   Note: ``When the order of knighthood was conferred with full
         solemnity in the leisure of a court or court or city,
         imposing preliminary ceremonies were required of the
         candidate. He prepared himself by prayer and fasting,
         watched his arms at night in a chapel, and was then
         admitted with the performance of religious rites.
         Knighthood was conferred by the accolade, which, from
         the derivation of the name, would appear to have been
         originally an embrace; but afterward consisted, as it
         still does, in a blow of the flat of a sword on the
         back of the kneeling candidate.'' --Brande & C.

Source : WordNet®

knighthood
     n : aristocrats holding the rank of knight