Supply can be defined as the quantity that a firm would offer for sale at a certain price during a certain time period. It means to express supply of a commodity, we should specify quantity the firm wants to offer for sale, price at which and time period during which the quantity is to be offered for sale. Supply can be defined as the desire for money backed up by ability to produce and willingness to offer for sale.
Supply is dependent upon different factors like prices of raw materials, wage rate, interest rate, expected profit margin, taxes and so on. But supply is basically written as function of price s=f(p).