Please explain web api

Hi suppose there are only two computers in the world on two different continents: each of them is windows 7 with SQL server and Visual studio and IIS and no firewall ; two developers click click mvc web app and publish to IIS; then each developer can navigate to the other's website. Based on this scenario can some one please explain to me with minimum technicality and jargon what is wep api? restful? my understanding is that both websites are restful and web api( developers have annotated the actions with get post put delete)