component

This term is defined in ECSS-E-ST-10-12C as
device that performs a function and consists of one or more elements joined together and which cannot be disassembled without destruction

This term is defined in ECSS-E-ST-35C Rev. 1 as
smallest individual functional unit considered in a subsystem

This term is defined in ECSS-Q-ST-70-08C as
device which performs an electronic, electrical or electromechanical function and consists of one or more elements joined together and which cannot normally be disassembled without destruction

This term is defined in ECSS-S-ST-00-01C as
set of materials, assembled according to defined and controlled processes, which cannot be disassembled without destroying its capability and which performs a simple function that can be evaluated against expected performance requirements

This term is defined in ECSS-E-ST-33-11C Rev.1 as
smallest functional item in an explosive subsystem