Noun
subfunction (plural subfunctions)
A secondary or subsidiary function.
Luc Steels writes: "A component has a particular functionality but this is not recognizable as a subfunction of the global functionality. Source: Internet
The network interface card may allow the service to function only on WiFi, only on Ethernet, or both. citation Linux Wake-on-LAN support may be changed using a subfunction of the ethtool command. Source: Internet