A family is a rank in the biological taxonomy of all organisms. Each family is split into Genera, the plural for genus. There are multiple families in each order. Usually, the name of the family ends with a "idae" for animals, and "aceae" for plants. There are also subfamilies and superfamilies. Subfamilies end with "inae".
In Latin, family is "familia".
For example, walnuts and hickories both belong to the walnut Family.