tree mouse

noun

1. : any of numerous small arboreal myomorph rodents: as

a. : any African long-clawed murid of Dendromus or related genera

b. : either of two cricetids of western No. America that are congeneric with the lemming mice

c. : any of a genus (Vandeleuria) of tropical eastern Asian climbing murids with very long tails and the great toe of the hind foot opposable and resembling a thumb

2. : white-breasted nuthatch