The term 'highway entrance' can be broken down into two crossword solutions: 'RAMP' (4 letters) and 'onramp' (6 letters). A RAMP is a sloped surface that connects two different levels of a roadway, allowing vehicles to transition from one level to the other. An onramp is a specific type of RAMP that allows vehicles to enter a highway from a lower-level road. Onramps are typically marked with signs and arrows to indicate the direction of travel.