两个概念,如果一个概念的外延全部包含在另一个概念的外延之中,那末,这两个概念之间就存在着包含和被包含的关系。其中外延较大的那个概念叫做包含概念,也叫属概念;外延较小的那个概念叫被包含概念,也叫种概念。概念之间的这种包含和被包含的关系叫做属种关系。如“名词”的外延全部包含在“实词”的外延之中,“实词”是属概念,“名词”是种概念。 Two concepts, if the extension of a concept is contained in the extension of another concept, then there is an inclusion and an inclusion relationship between these two concepts. The concept in which the extension is larger is called inclusion concept, also called concept; the concept with smaller extension is called inclusion concept, also called concept. This inclusion and inclusion of relationships between concepts is called genera relations. For example, the extension of “noun” is all contained in the extension of “real word”. “Real word” is a concept, and “noun” is a concept.