This is an online database, sponsored by the US Department of Labor's Employment and Training Administration; which has occupational definitions to help and match job seekers with jobs. 

What occupational Information Network can be used for

Occupational Information Network can be used by many different people for a various reasons:

• Writing and updating job descriptions and job specifications
• Developing criteria for recruitment and selection
• Developing criteria for performance appraisal systems
• Structuring training and development activities
• Structuring compensation systems
• Improving career counselling