1a sum of money granted by the state or a public body to help an industry or business keep the price of a commodity or service low:a farm subsidy [mass noun]:the rail service now operates without subsidy
a sum of money granted to support an undertaking held to be in the public interest:she was anxious about her Arts Council subsidy [mass noun]:the arts continued to thrive through public subsidy
a grant or contribution of money:the position is generously rewarded and benefits include a mortgage subsidythe country’s economy is near to collapse after the end of Soviet subsidies
2 historical a parliamentary grant to the sovereign for state needs.
a tax levied on a particular occasion.
late Middle English: from Anglo-Norman French subsidie, from Latin subsidium 'assistance'
subsidy in other Oxford dictionaries
Definition of subsidy in the US English dictionary