back clearance


  1. Machinery.
    1. the gradual termination of a groove on the body of an object not ending there, as the upper termination of a flute in a twist drill.
    2. Also called back clearance.a space in a depressed area of an object into which a machine tool or grinding wheel may safely enter at the end of a pass or operation.
  2. the merging of a curved surface into another surface.
  3. an act or instance of running away so as to evade, abandon, or avoid something.
  4. a person who runs away so as to avoid payment or duty.
  5. an act or instance of expiring or becoming depleted: the runout of a union contract; a runout in office supplies.
  6. uneven wear on the outer edges of a tire or on the rim of a wheel.

Origin of runout

First recorded in 1925–30; noun use of verb phrase run out Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018