Merriam-Webster Collegiate Dictionary - arbor

 I. noun  Etymology: Middle English erber, herber garden, from Anglo-French, from herbe herb, grass  Date: 14th century a shelter of vines or branches or of latticework covered with climbing shrubs or vines  II. noun  Etymology: Latin, tree, shaft  Date: 1659  1. a spindle or axle of a wheel  2. a main shaft or beam  3. a shaft on which a revolving cutting tool is mounted  4. a spindle on a cutting machine that holds the work to be cut