Traditionally, it refers to management consulting (MBB, business wings of the Big 4, etc.).
Now, IT services companies all call themselves consulting. Accenture and Booz-Allen are 2 major US players, and a bunch of Indian labor dealers (Infosys, Tata, etc.). They hire software developers and send them to Federal government agencies, banks and all sorts of companies that don't want to hire these roles permanently.
