What is a condition, restriction, or requirement that the system must satisfy?

The term that fits the description of a condition, restriction, or requirement that the system must satisfy is indeed a constraint. In systems analysis and design, constraints define the boundaries within which the system must operate. These can include limitations on resources, technology, regulatory demands, time, budget, and other factors that may affect project outcomes. Recognizing and documenting constraints is crucial for ensuring that the development stays aligned with stakeholder expectations and capabilities.

In contrast, milestones refer to key points in a project timeline that signify important phases or deadlines, while use cases describe how users will interact with a system, detailing specific scenarios. Document review is a process for evaluating project documentation for completeness and accuracy but does not convey a requirement that the system must fulfill. Constraints are fundamental in shaping the system's design and implementation strategy, making them essential to project success.