Family, as it relates to taxonomic rank, is between order and genus. Family, then, designates a category of classification that is fairly precise. For example, family would include categories, such as apes and lemurs. They are similar. So within the primate order, the family of apes occurs. Family can also consist of a collection of members in a household (i.e., parents and children). In chemistry, a family is a group of elements with similar properties.