The Collaborative International Dictionary of English v.0.48:

Trad \Trad\, obs.
   imp. of Tread. --Chaucer.
   [1913 Webster]

WordNet (r) 3.0 (2006):

trad
    n 1: traditional jazz as revived in the 1950s

Bouvier's Law Dictionary, Revised 6th Ed (1856):

TRADE. In its most extensive signification this word includes all sorts of
dealings by way of Bale or exchange. In a more limited sense it signifies
the dealings in a particular business, as the India trade; by trade is also
understood the business of a particular mechanic, hence boys are said to be
put apprentices to learn a trade, as the trade of a carpenter, shoemaker,
and the like. Bac. Ab. Master and Servant, D 1. Trade differs from art.
(q.v.)
     2. It is the policy of the law to encourage trade, and therefore all
contracts which restrain the exercise of a man's talents in trade are
detrimental to the commonwealth, and therefore void; though he may bind
himself not to exercise a trade in a particular place, for, in this last
case, as he may pursue it in another place, the commonwealth has the benefit
of it. 8 Mass. 223; 9 Mass. 522. Vide Ware R. 257, 260 Com. Dig. h.t.; Vin.
Ab. h.t.