Is there a?difference between cervical disc herniation and cervical disc encroachment?

Similar: Cervical disc herniation can produce encrachment of the nerve root, however you can have encroachment due to other causes such as osteophytes(bone spurts).

No: A cervical disc can encroach on the spinal canal occupying space that potentially can compromise the spinal cord or cervical nerve root or roots. So it means the same if I am understanding your question correctly.

Same: To me, both terms describe a disc pathology that can compress the nerve or spinal cord. Check out spine-health.Com.