proverbially

from WordNet (r) 3.0 (2006)

proverbially
    adv 1: in the manner of something that has become a byword;
           "this proverbially bitter plant, wormwood"

from The Collaborative International Dictionary of English v.0.48

Proverbially \Pro*ver"bi*al*ly\, adv.
   In a proverbial manner; by way of proverb; hence, commonly;
   universally; as, it is proverbially said; the bee is
   proverbially busy.
   [1913 Webster]