What does "arbor" mean?

Arbor: (Bot.) A tree, as distinguished from a shrub.

Additional senses

  1. 2.Etym: [Cf. F. arbre.] (Mech.) (a) An axle or spindle of a wheel or opinion. (b) A mandrel in lathe turning. Knight. Arbor Day, a day appointed for planting trees and shrubs. [U.S.]

Sources