A Requirements Traceability Matrix (aka "Trace Matrix") enables you to represent the relationships between requirements artifacts planned for a release. Examples include:
Trace Matrix will show the relationship between records in X-axis and Y-axis by placing a "checkmark" in the appropriate cell in the matrix. Records that are "orphans" - i.e. not linked to any records in the other axis will be marked with light-red background to flag them.
Here's an example of a traceability matrix between "Features" and "Requirements" planned for a specific release:
The matrix above displays the relationships between the records in the two axes:
Benefits of Traceability Matrix: