Across the many fields concerned with interactivity, including information science, computer science, human-computer interaction, communication, and industrial design, there is little agreement over the meaning of the term "interactivity", but most definitions are related to interaction between users and computers and other machines through a user interface. Interactivity can however also refer to interaction between people. It nevertheless usually refers to interaction between people and computers – and sometimes to interaction between computers – through software, hardware, and networks.

Multiple views on interactivity exist. In the "contingency view" of interactivity, there are three levels:

1. Not interactive, when a message is not related to previous messages.
2. Reactive, when a message is related only to one immediately previous message.
3. Interactive, when a message is related to a number of previous messages and to the relationship between them.

One body of research has made a strong distinction between interaction and interactivity. As the suffix 'ity' is used to form nouns that denote a quality or condition, this body of research has defined interactivity as the 'quality or condition of interaction'. These researchers suggest that the distinction between interaction and interactivity is important since interaction may be present in any given setting, but the quality of the interaction varies from low and high.