Definition
The term 'out-of-door' is an older, somewhat archaic way of saying 'outdoor.' It means relating to or being in the open air, outside of buildings. It's essentially a synonym for 'outdoor,' but it's less commonly used in modern English. Think of 'out-of-door' activities as those that take place outside, like picnics, gardening, or hiking. It emphasizes the contrast between being inside and being in the open air. While 'outdoor' is the more common and widely understood term, 'out-of-door' can still be found in older literature or in more formal contexts.