LEC stands for Local Exchange Carrier, which is a regulatory term for companies that provide phone service or transport data. These companies are broken up based on how long they have been providing service. Companies from before 1996 are ILECs (Incumbent Local Exchange Carriers), and after are CLECs (Competitive Local Exchange Carriers). The two have different titles because they have different regulatory restrictions upon them.

It is important to note that LEC can also have other meanings, such as "drizzle; mist" or "the distribution of light and shade in a picture". However, in the context of telecommunications, LEC refers to Local Exchange Carrier.