Crosscutting Concern

In software engineering, a crosscutting concern is a requirement or feature that affects multiple modules of a system and cannot be cleanly decomposed into a single component. Accessibility is a classic crosscutting concern because requirements like providing text alternatives, ensuring keyboard navigation, and maintaining sufficient colour contrast must be applied across many different parts of a web application rather than being isolated in one place. Aspect-oriented software development (AOSD) was created specifically to handle crosscutting concerns by modularising them into reusable "aspects" that can be systematically applied across a codebase.