My Ignorance is Showing

So I'm 150 pages into Crime and Punishment, and I land on the word "dormouse." I always thought it was "door mouse," though whose door I thought the rodent lived in or under, I'm not sure.

So I look up the word. And I learn that the little creature is thought to be dormant in winter, entering a semi-hibernation, so it probably got its one-word name from people hearing "dormant mouse" and thinking it to be a species of mouse rather than a modifier + "mouse."

Dormouse. One word. Not to be confused with the two-word church mouse--as in "poor as a."