The term 'Focus of Activity' can be summarized as a HUB, which is a three letter word. A HUB is a central point or location where people, activities, or information converge and from which they radiate outwards. It is often used to refer to a place where multiple transportation routes meet, such as an airport or train station. In terms of activity, a HUB is a place where people come together to work on a project or to share ideas. It can also refer to a center of communication, such as a website or online forum.