What is (a) A small circular saw. (b) A triangular chisel. (c) A drill with a serrated head larger than the shank; -- used by dentists called?

bur — (Mech.) (a) A small circular saw. (b) A triangular chisel. (c) A drill with a serrated head larger than the shank; -- used by dentists. (Webster's 1913.)

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