outdoor
Happening or used outside, not inside a building.
Outdoor describes anything that happens outside rather than inside a building. When you play outdoor games like tag or soccer, you're running around in the fresh air instead of staying indoors. An outdoor concert takes place in a park or stadium rather than inside an auditorium.
The word can describe activities, spaces, or equipment. Outdoor furniture is built to withstand rain and sun. Outdoor education programs teach skills like camping, hiking, and reading maps in nature. Some people are real outdoor enthusiasts who love spending time hiking, fishing, or exploring wilderness areas.
Notice that outdoor suggests embracing the natural environment: the weather, the landscape, the seasons. An outdoor classroom means learning that takes advantage of being outside, maybe studying plants up close or observing cloud formations, rather than simply moving desks to a patio.
The opposite is indoor, and people often talk about indoor-outdoor spaces that blend the two, like a covered porch or a restaurant with walls that open to a garden. Many kids naturally love outdoor play because it offers space to move, explore, and experience the world beyond walls and screens.