/run"owt'/ , n.
1. Mach.
a. 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.
b. 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.
[ 1925-30; n. use of v. phrase run out ]