The Hidden Difference Between Shadow and Shade
While we use the terms interchangeably, they describe different physics. A shadow is a dark projection on a surface, while shade is the actual three-dimensional volume of space hidden from light.
Think of shade as the actual pocket of protected space behind a building or a tree where light cannot reach. A shadow, by contrast, is merely the flat, two-dimensional silhouette that appears on the ground or a wall as a result. This distinction is vital in architecture for managing heat and light. By understanding these volumes, designers can create cooler, more comfortable environments for people to inhabit.
Source: Shadow