In my understanding AI is an even broader term and means "any solution that imitates intelligent behavior". E.g. expert systems which are pretty much a bunch of if-then rules are also considered AI.
It's why I use "AI" and "ML" interchangeably although I know it's technically incorrect - the formal definition doesn't match what people are currently thinking.
So yes, "any solution that imitates intelligent behaviour" is probably right, but with nuances with regard to what that actually means.