Dear Jagjit

Nice question.

The word Relations implies that there are two or more parties involved in the process.

We normally come across with Industrial Relations, Customer Relations, Public Relations,Supplier Relations and Employee Relations.

Industrial Relations in a broader context defines relationship between employer and employer, between employer and employees and employees and employees.
Employee relations is a subject of Industrial Relations. It involves welfare for employees, terms and contracts with employees, employee development,employee productivity and so on.
Industrial Relation includes all, but the focus is more on Union.In Employee Relations, the focus is more on Employees

Anurag