A male donkey or ass is called a jack, a female a jenny or jennet; a young donkey is a foal. Jackdonkeys are often used to mate with female horses to produce mules; the biological "reciprocal" of a mule, from a stallion and jenny as its parents instead, iscalled a hinny. read more
A donkey and an ass aren’t quite the same thing. An ass is a smaller relative of the horse, with longer ears and a shorter mane. A donkey is a domesticated ass. read more
The donkey is ass. In American English these words merged into a single ass. The etymology has nothing to do with the similarity of the animal to a behind. read more