DTH reactions may include, but are not limited to, contact dermatitis (eg, poison ivy rash), tuberculin skin test reactions, granulomatous inflammation (eg, sarcoidosis, Crohn disease), allograft rejection, graft versus host disease, and autoimmune hypersensitivity reactions.
tricks of the trade. 1  Clever ways of operating a business or performing a task or activity, especially slightly dishonest or unfair ones. For example, Alma knows all the tricks of the trade, cutting the fabric as close as possible, or The butcher weighs meat after it's wrapped; charging for the packaging is one of the tricks of the trade.
DEFINITION of 'Trade'. A basic economic concept that involves multiple parties participating in the voluntary negotiation and then the exchange of one's goods and services for desired goods and services that someone else possesses.he advent of money as a medium of exchange has allowed trade to be conducted in a manner that is much simpler and effective compared to earlier forms of trade, such as bartering. In financial markets, trading also can mean performing a transaction that involves the selling and purchasing of a security.