slider
n.— «The Rizr, also fashioned after the Razr, is what’s called a “slider,” a type of phone on which Motorola has lagged. With a slider, a user opens the phone by sliding a cover to reveal a keyboard, not by flipping it open.» —“Razr kids trotted out” by Mike Hughlett Chicago Tribune July 25, 2006. (source: Double-Tongued Dictionary)