-Habitat- is probably the most common term in ecological research. Elementary school students are introduced to the term, college students study the concept in depth, hunters make their plans based on it, nature explorers chat about the different types, and land managers spend enormous time and money modifying and restoring habitats. Although a broad swath of people now have some notion of what habitat is--opening up ample opportunity for further education and conservation--the scientific community has by and large failed to define it concretely, despite repeated attempts in the literature...