Acknowledgment of Receipt.
It's an important milestone and usually comes about 2 months after you submit your wife's application. It's important because it means the application has passed an initial screening and appears to be complete. Until you receive AOR, you cannot be sure the IRCC won't finding some defect or something missing in your application and it will be returned, leaving you to start all over again.
I have returned to edit this post. I referred to "your wife's application", but notice she is your fiancé. You get the idea. I won't change the wording of the above paragraph.
A small point of language, and as someone with a gf from the Philippines, you should know that she is "Filipino", not "Philippino". A common error and quite understandable. Carrying on, a male Filipino is a Filipino. A female is a Filipina. But both are Filipinos, if that makes any sense.