what does genus mean what does genus mean?

"Genus" comes from a Latin Word that means something like "family."

It's the first half of the Linnaean binomial taxonomy.

So, for example, domestic cats are Felis catus. (The genus name is always capitalized, the species name is always not.) The closely related wildcat is Felis silvestris. The also closely related sand cat is Felis margarita. The somewhat more distantly related lion, while still a felid, is in a different genus, Panthera (specificially, Panthera leo).