Low-viscosity, multi-weight oils are becoming more common each day, and cars like the 2014 RAV4 use these oils to maximize fuel efficiency. In the 2014 RAV4's case, it uses about the lowest weight oil that an internal-combustion engine can use. This not only helps the oil to flow to all of the components upon start up in cool weather, but also helps it achieve the 31-mpg highway rating the EPA gave it.
Toyota recommends using 0W-20 engine oil in the Toyota RAV4, but you may use 5W-20 as a substitute if 0W-20 is unavailable. Including the oil filter capacity, the RAV4 requires 4.6 quarts of oil to fill it. Toyota does not specify synthetic oil, but you may use it if you wish.