A cellphone usually connected under someone else's identity to conduct shady and illegal activity on and to avoid leaving a trail to the user. Depending on the carrier the phone is connected to, a burner can last up to 1 - 2 months before it is cut-off due to non-payment.
Dawg! You got a hook-up on burner phones? I'm deep in this street game, so I need a new one every week!