What belongs to a family—or if a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family. Taxonomists often take different positions about descriptions, and there may be no broad consensus across the scientific community for some time. The publishing of new data and opinions often enables adjustments and consensus.
The naming of families is codified by various international bodies using the following suffixes:
- In fungal, algal, and botanical nomenclature, the family names of plants, fungi, and algae end with the suffix "-aceae", with the exception of a small number of historic but widely used names including Compositae and Gramineae.
- In zoological nomenclature, the family names of animals end with the suffix "-idae".