Haha, I know you know it’s a property of an instance!
"To declare a property, use the let keyword. A property has a name, followed by a colon and then the kind of data it holds. This property’s name is day, and it holds a String."
In #Swift, kinds of data are called types. You can read the code you added to an structure like this: “day is a property whose type is String.” Or you could say, “day is a property of type String.”