The word "Oreo" is a brand name for a popular type of cookie. It is made up of two chocolate cookies with a sweet, creamy filling in the middle. Full definition
Since it's an update to the app itself, any watches that have received the Android Oreo Android Wear update should be receiving this update. (digitaltrends.com)
It also mentions the timeline for Android Oreo update of Samsung's several other smartphones including Galaxy A7 (2017), Galaxy A5 (2017) and Galaxy A3 (2017) as two - year old Galaxy S7, Galaxy S7 Edge. (indianexpress.com)
No big deal here too, the phone runs on near stock Android Nougat 7.1.1, with a promise of Oreo update in the first quarter of 2018. (suggestphone.com)