Definition of dummy

i. A short piece of core or core-size cylinder of rubber or other material placed in the core lifter in an empty core barrel to guide the first part of a newly cut core into the core lifter.

Synonym of: guide core

ii. A cathode, usually corrugated to give variable current densities, which is plated at low current densities to remove preferentially impurities from a plating solution.

Ref: ASM, 1

iii. A substitute cathode that is used during adjustment of operating conditions.

Ref: ASM, 1