Rabbits

• Hares
• Pikas
• Formerly considered the suborder Duplicidentata of the order Rodentia

Wikipedia Word definitions in Wikipedia
The lagomorphs are the members of the taxonomic order Lagomorpha , of which there are two living families : the Leporidae ( hares and rabbits ) and the Ochotonidae (pikas). The name of the order is derived from the Ancient Greek lagos (λαγώς, "hare") + ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Lagomorpha \Lag`o*mor"pha\ (l[a^]g`[-o]*m[^o]r"f[.a]), prop. n. pl. [NL., fr. Gr. lagw`s a hare + morfh` form.] (Zo["o]l.) an order of rodent-like mammals, comprising the hares, rabbits, and pikas. They have four incisors in the upper jaw. Called also Duplicidentata ...