Microinteraction

http://microinteractions.com/what-is-a-microinteraction/

Functional animations in UX design

"Functional animation is subtle animation that we embed in a user interface design as part of our process.

A good UX designer can easily explain the logic behind each decision in a design concept. This includes the information architecture, the hierarchy of page content, the flow and the assumptions made."

http://www.smashingmagazine.com/2015/05/14/functional-ux-design-animations/