: an act, process, or methodology of making something (such as a design, system, or decision) as fully perfect, functional, or effective as possible specifically : the mathematical procedures (such as finding the maximum of a function) involved in this.

What does it mean to optimized?

transitive verb. : to make as perfect, effective, or functional as possible optimize energy use optimize your computer for speed and memory— Charles Brannon.

What does optimizing your phone mean?

The short story is that Android is doing what it says, creating an optimized version of each app for the new version of Android you just upgraded to. This process makes each app start as fast as possible with the new Android version.