Design
Interaction Design
Plain-language definitionThe design of how a person and product respond to one another over time. It covers states, feedback, input, errors, motion, and recovery.
Why it matters
Use the term to make a better decision.
In practice, interaction design matters when a team needs to connect a technical or creative choice to a visible change in clarity, performance, discovery, or conversion. The useful question is not whether the term sounds sophisticated. It is what decision it helps the team make.