basically to pay money in support of something. more specifically, to pay some of the cost of production to make something cheaper for the buyer. the most common example of this is us government subsidies--the state gives money to farmers producing basic commodities (corn, wheat, etc.), which in turn lowers the price of buying those commodities. this may seem like a great idea, but we end up paying that extra money anyway in the form of taxes--whether we use those products or not. this also makes un-subsidized farmers' (usually ones in mexico or other central american countries) goods more expensive.