a bar, shaft, or axis that holds, turns, or supports a rotating cutting tool or grinding wheel, often having a tapered shank fitting tightly into the spindle of a machine tool. Compare mandrel.
b.
a beam, shaft, axle, or spindle.
2.
Metallurgy. a reinforcing member of a core or mold.
Origin: 1650–60; respelling, by association with arbor3, of earlier arber, arbre < French,Old French < Latinarbor wooden beam or part in an olive press, tree
c.1300, herber, "herb garden," from O.Fr. erbier "kitchen garden," from L. herba "grass, herb" (see herb). Later "a grassy plot" (early 14c., a sense also in O.Fr.), "a shaded nook" (mid-14c.). Probably not from L. arbor "tree," though influenced by its spelling.