What is the definition for genus?

In Biology, a genus can be defined as a grouping of organisms that differentiate them from other organisms. Biologically speaking, the genus is the grouping just before the species. For instance, the tiger, the lion, the jaguar, and the leopard, all of which are different species, belong to the same biological genus: Panthera.

In general use, genus refers to "a class of things that have common characteristics and that can be divided into subordinate kinds." (Source: google)