Class

The term class has various meanings when encountered in different scientific fields. These include:

1. In biology, a group of related or similar organisms. A class contains one or more orders. A group of similar classes forms a phylum.
2. In sociology, a large group of people differing from each other by the place they occupy in a historically determined system of social production, by their relation (in most cases fixed and formulated in law) to the means of production, by their role in the social organisation of labour, and, consequently, by the dimensions of the share of social wealth of which they dispose and the mode of acquiring it.
3. In starship terminology, a set of vessels in a starfleet that share essentially the same design. See Starship classes.
4. In planet classification, a system used by some Alpha Quadrant civilizations to label planets by their habitability. Examples include Class M and Class H.