Runaway is someone who runs away from a place. It may be from home. A runway is where an airplane takes off. It could also be a platform where models walk in a fashion show.

runaway: usually used to describe a child who left home without permission and without telling anyone runway: The long, wide cement road you find at an airport that is used by airplanes to land on and take off from. runway(also meaning): The stage used by fashion models. It is placed in the centre of the room and the models walk down it and back to show off their designer outfits. run away(the one you did not ask): a short way to describe the action of someone running away from something or someone.

A runaway is a person. The word is usually used to refer to a teenager or young person who has run away from home. A runway is a thing. It can be the landing strip where planes take off and land, or it can be the walkway that models walk on during a fashion show.

a runaway = someone who has run away from home (or similar) a runway = where a plane takes off www.thefreedictionary.com

"runaway" can also be an adjective, as in "a runaway train" = a train which is going very fast and out of control. Or "a runaway success", which means a big success.