*arbor vitae*

‖ [ L., tree of life. ] 1. (Bot.) An evergreen tree of the cypress tribe, genus Thuja. The American species is the Thuja occidentalis. It is commonly used as an ornamental shrub around homes. [ 1913 Webster +PJC ]

2. (Anat.) The treelike disposition of the gray and white nerve tissues in the cerebellum, as seen in a vertical section. [ 1913 Webster ]