In software designing crosscutting concerns are concerns (requirements) that span over many layers (tiers) of your application.
Generally, the majority of the application functionality will be arranged in tiers and there will be some functionalities (examples below) that would span across those layers. these are crosscutting concerns.
- Exception handling
It is important to consider how crosscutting concerns are facilitated at the design stage to avoid untidy and unreadable solutions.
This Microsoft article explains the topic further and also explains methods to handle common crosscutting concerns.