A rodent is a small animal with two long, very sharp front teeth that never stop growing, so it has to keep biting hard things to wear them down. Rats, mice, squirrels, beavers, and hamsters are rodents.

A rodent rodent（囓齒動物） is a small animal with two long, very sharp front teeth是一種小動物，有兩顆長長、很尖銳的門牙，that never stop growing這兩顆牙齒會一直長，so it has to keep biting hard things to wear them down所以牠必須不斷啃咬硬物把牙磨短。Rats, mice, squirrels, beavers, and hamsters are rodents老鼠、松鼠、河狸、倉鼠都是rodent。

People often put rabbits in the same group too — some learner dictionaries even say “a rat or a rabbit” — though actually a rabbit is not a true rodent; it belongs with hares, in a different family. Scientists care about that split; everyday English often does not.

People often put rabbits in the same group too人們常把兔子也算進同一類——some learner dictionaries even say甚至有些學習型字典會寫「a rat or a rabbit」老鼠或兔子——though actually不過其實a rabbit is not a true rodent兔子並不是真正的rodent；it belongs with hares, in a different family牠跟野兔算是另一個不同的科。Scientists care about that split科學家很在意這個分別；everyday English often does not但日常英語常常不區分。

You also hear rodent as a describing word: rodent teeth, a rodent problem in the kitchen. It is a calm, slightly school-book word. Nobody calls a pet hamster “my rodent” for fun.

You also hear rodent as a describing word你也會聽到rodent當形容詞用：rodent teeth（囓齒動物的牙齒）、a rodent problem in the kitchen或廚房裡的a rodent problem（鼠患問題）。It is a calm, slightly school-book word這是個平淡、有點學術味的字。Nobody calls a pet hamster "my rodent" for fun沒有人會開玩笑地把寵物倉鼠叫做「my rodent」。