One whole branch of environmental anthropology has followed the path suggested by this definition of culture, developing increasingly sophisticated by this definition of culture, developing increasingly sophisticated studies of cultural knowledge. Cognitive anthropologists developed their methods by studying relatively small and closed sets of terms such as the words used for naming colors or classifying kinship relations. Each of these sets of terms is called a semantic domain, that is, an area of meaning in a language. The studies that are most numerous and relevant to us are studies of taxonomy, that is, the way that people name and classify plants and animals. This kind of study is called ethnoecology or ethnobiology.