Every industry has its own set of typically used words that employees use among themselves to refer to things. Most of these words actually develop as slangs and are indeed considered slangs, but they have also found a place for themselves in the industry's lingos.
For instance, the Oil Field employees have been known to develop slangs for objects related to their line or work that have almost become a part of their regular conversation. In an Oil Field, a fish is referred to something that has been either dropped or has been ;ost inside a wellbore while the act of getting it out is, unsurprisingly called fishing.