The word synthetic is crucial here. 5W-20 synthetic motor oil is made of synthetic base oil (refined and modified hydrocarbon atoms) and additives. The synthetic base oil and various additives make it more stable in hotter climates so it can better protect against engine wear and tear. Synthetic motor oil also lasts longer than conventional oil.
If you’re looking to save a little bit of money, you could opt for a 5W-20 synthetic oil blend. It tends to be cheaper than synthetic motor oil but protects better and lasts longer than conventional oil. Keep in mind that you should never switch lubricants—so don’t choose 5W-30 in a pinch, for example.