Hi Muhammad,
I completely agree with Shames. I have tried to put down the definitions from various sources but you can also visit the links provided to acquire more details -
Simply put, an Organization Development practitioner is to an organization as a physician is to a human body. The practitioner "diagnoses" (or discovers) the most important priorities to address in the organization, suggests a change-management plan, and then guides the organization through the necessary change. There are different definitions and views on how the change should occur.
Human Resource Development is the framework for helping employees develop their personal and organizational skills, knowledge, and abilities. Human Resource Development includes such opportunities as employee training, employee career development, performance management and development, coaching, succession planning, key employee identification, tuition assistance, and organization development.
What is Organization Development?
What Is Human Resource Development - Definition of Human Resource Development
Human Resource Development