The phrase "frozen berries" refers to fruits, like strawberries or blueberries, that have been picked and then frozen to preserve them. Full definition
When using frozen berries in recipes that do not require cooking, thaw well and drain prior to using. (whfoods.org)
Plus, we like to stock the freezer with frozen berries for the off - season and those days when you just have to have dessert. (mywifecancook.com)
The use of frozen berries means the taste of summer can make an appearance at any time of year and it literally appears out of nowhere in less than 5 minutes! (ourkitchen.fisherpaykel.com)