Well, see, that still doesn't make sense. Firstly, because rabbits are in the family Leporidae and not vice versa, and secondly, because adding "word" in front of "rabbits" changes the meaning of the sentence.Actually, it would be "the family Lepordiae is part of the word Rabbits". Since rabbits is the term that we use to refer to many different species of animals.
"Rabbits" and "the word 'rabbits'" are two, very different, objects.