I don't know an actual definition, but this might help: APPROACH is as you are coming closer and closer, eg, the boat is approaching the dock. It is not there yet, but it is coming closer and closer. COME is just a more general word, you are going from some other place to 'here' eg, he is coming to visit us this evening (come can be used also for going somewhere with others eg come with us on our trip, come with me to the store) REACH, GET(to a destination), and ARRIVE are very similar, they imply you made it to the final destination. I reached my goal, I arrived home, I finally got there. REACH implies you were farther away and you finally reached the destination. Often it is used in a context where there were difficulties in the way. But not necessarily. It implies the goal is achieved, you reached your destination. eg Despite the storm on the sea we reached the shore safe and sound. GET (to a destination) means you made it there, you arrived. I got home at 10 ARRIVE means you got there. It is used also in a context of transportation, like planes, buses, trains. eg I arrived at 10 / The bus is scheduled to arrive at 10