rodent’s jaw: rat
diastema 
Large space between the incisors and the premolars due to the absence of canines.
molar 
Large tooth with several roots; it is located at the back of the jaw behind the premolars and used to grind food.
incisor 
Flat, constantly growing tooth with a single root; it is located in the front of the jaw and used for cutting up plants.
premolar 
Tooth usually with a single root; it is located behind the diastema and used for grinding.