"If it's short, it's more likely to actually be used."

An interface is defined as "a surface regarded as the common boundary of two bodies, spaces, or phases" (Dictionary.com).  In the design world, an interface is regarded as the platform being used, such as a computer, smartphone, or tablet. The interface is, essentially, the common boundary between multiple users.

Interaction design is simply the design of something on an interface that the user will actually be interacting with, such as a web site or application. Interaction design includes how the user will interact with the product, for what purpose, and what happens after they interact. Steve Krug defines this as "what happens when the user clicks".

Information architecture is the way how everything within a website or application is organized. This includes actual placement of information, as well as navigation among different information. This organization is important because it brings the entire website or application together and makes it functional for the user. The most effective way to begin the organization is with a site map.

Krug defines usability as "really just making sure that something works well: that a person of average (or even below average) ability and experience can use the thing for its intended purpose without getting hopelessly frustrated". This means that the information architecture must be organized, sensible, and flow well, and interaction design must be easily understandable and interact as the user expects or needs.