Word Origin and History for semi-Expand before vowels sem-, word-forming element meaning half, part, partly; partial, imperfect; twice, from Latin semi-half, from PIE *semi-half (cf. Sanskrit sami half, Greek hemi-half, Old English sam-, Gothic sami-half).
Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, hamsters, gerbils and capybaras. Other animals such as rabbits, hares, and pikas, whose incisors also grow continually, were once included with them, but are now considered to be in a separate order, the Lagomorpha.
A rodent is an animal with two sharp, constantly growing incisors.  These teeth are kept short by gnawing. Rodents include rats, mice,  hamsters and gerbils. They are mostlyâ¦ very small, although the  biggest rodent is the capybara, which can grow to up to 4.3 feet.  Canine ancestors may be a rodent or rodent related.