In the ordinary sense, both desire and requirement are used in the same sense, but in economics, these two words are different. Effective desire in economics is considered as a necessity.
Three things are necessary for effective desire :
1. the desire to obtain something
2. adequate means to satisfy the .desire
3. the readiness to spend for fulfilling the desire.
If one thinks about buying a car then it is his wish, but if he has enough currency to buy a car and is willing to spend the money on buying that car, then the desire for the car becomes his necessity.
