Full Idea
Time is not change, but it is an aspect of change.
Gist of Idea
Time is an aspect of change
Source
Aristotle (Physics [c.337 BCE], 219a09)
Book Reference
Aristotle: 'Physics', ed/tr. Waterfield,Robin [OUP 1996], p.105
A Reaction
I can't think of a better definition of time. Intuition says that time could continue when all change stopped (the 'frozen worlds' thought experiment), so that we can distinguish time from the change that gave rise to it (or the idea of it).