In systems analysis and computer networking, what is the standard term for the shared boundary where two separate systems, devices, or software components meet and interact with one another?

Introduction / Context:
Software, hardware, and human-computer systems communicate across well-defined boundaries. Naming and understanding that boundary clarifies responsibilities, protocols, and data formats. This is foundational for API design, device drivers, and system integration projects.

Given Data / Assumptions:

• Two distinct systems or subsystems must exchange information or control signals.
• The boundary includes rules (protocols), physical connectors or function signatures.
• We seek the conventional term used across engineering disciplines.

Concept / Approach:

An interface is the point or region of interaction between systems. In software it may be an API or message schema; in hardware it may be a bus connector or pinout; in user experience it is the graphical or command interface. Clear interface definitions enable modularity and independent development.

Step-by-Step Solution:

Verification / Alternative check:

Examples include USB interface specifications, RESTful API interfaces, and OS device-driver interfaces, each formalizing expectations at the boundary.

Why Other Options Are Wrong:

• Surface: generic geometric term; not specific to inter-system communication.
• Interdiction: means prohibition or interception; unrelated to system boundaries.
• None: incorrect because 'interface' precisely describes the shared boundary.

Common Pitfalls:

• Equating interface with implementation. The interface specifies 'what', not 'how'.

Final Answer:

Interface.