A process is a set of interrelated or interacting activities which transforms inputs into outputs (ISO 9000:2005)
Process Purpose: high level objective of performing the process and the likely outcomes of effective implementation of the process. NOTE The implementation of the process should provide tangible benefits to the stakeholders. (ISO/IEC 12207:2008)
Process Outcome: observable result of the successful achievement of the process purpose (ISO/IEC 12207:2008)
ISO 9000, 2005. Quality management systems -- Fundamentals and vocabulary
ISO/IEC 12207, 2008. Systems and software engineering -- Software life cycle processes
These definitions are taken from the INCOSE Systems Engineering Handbook, and are based on standard ISO terminology.