An order of mammals having two (rarely four) large incisor teeth in each jaw, distant from the molar teeth. The rats, squirrels, rabbits, marmots, and beavers belong to this order. [
1913 Webster]
" The incisor teeth are long, curved, and strongly enameled on the outside, so as to keep a cutting edge. They have a persistent pulp and grow continuously."
[1913 Webster]