What does arbor vitae mean?
The definition of arbor vitae
Ar”bor vi”tæ.
Etym: [L., tree of life.]

1 (Bot.)
An evergreen tree of the cypress tribe, genus Thuja. The American species is the T. occidentalis.
2 (Anat.)
The treelike disposition of the gray and white nerve tissues in the cerebellum, as seen in a vertical section.