is a multi-disciplinary profession that treats design from a systems perspective. Systems Engineers are employed to manage the architectural development of complex systems that involve multiple engineering disciplines. For example; the engineering of the space shuttle required Software, Electrical, Mechanical, Civil and Chemical Engineers. Systems Engineers were employed to partition the work appropriate to the various disciplines. A logical architecture was created and each logical component was assigned to be implemented as hardware (electrical, mechanical), civil, chemical or software.
A system is simply a collection of interacting components that are affected by and effect their environment.
This admittedly general definition includes all kinds of things that are not usually thought to be systems.
Here is a list of some diverse systems; trains, boats, planes, planets, businesses, networks, life forms, educational institutions, diapers, buildings, medical equipment, weapons, computers, mines, roads, etal.