Rabbits are not rodents.
Instead rabbits are mammals that are in the order of Lagomorpha.
Lagomorpha also includes pikas and hares.
On the other hand rodents are in a separate order called Rodentia which includes marmots, squirrels, rats and mice.
Rabbits also have 2 sets of upper incisors and rodents only have one set of incisors.
A rabbits incisors are also larger and more prominent than rodents incisors and has a smaller set of peg like teeth behind them.
Rabbits are also herbivores which eat grasses, leaves and other plant matter and their digestive system is adapted to high fiber diets.
Although until the early 20th century, rabbits and lagomorphs were classified as rodents but rabbits are not rodents at all.