Did you ever wonder what an Air Analyst does? Or maybe a breaker operator? What about an electric-bath attendant? For all of this occupations, or anyone you can think of (even yours), occupationalinfo.org has a definition.
This website claims to be the complete Dictionary of Occupational Titles (DOT), and judging for its amazing amount of occupations listed, it probably is. From Abalone Diver to wrong-address clerk, every job/occupation has a definition here. This is the revised fourth edition of the dictionary, which is supplied by the US Department of Labor. To find a job definition you can simply look for the jobs title, sorted in alphabetical order or by categories. The definitions are dictionary-like and some of them feature tasks, knowledge needed and skills. You can also find here all the numerical codes for each job, standard industrial classification, and a complete glossary to help understand better all the definitions. 
