Performance of activities, work, or duties.
Sources:
NIST SP 800-160v1r1
from
ISO/IEC/IEEE 15288:2015
A software component participating in a service-oriented architecture that provides functionality or participates in realizing one or more capabilities.
Sources:
NIST SP 800-95
under Service
from
Open Grid Services Architecture Glossary of Terms
A set of related IT components provided in support of one or more business processes.
Sources:
NISTIR 7693
under Service