A volcanic arc is a chain of volcanoes formed above a subducting tectonic plate, typically parallel to an oceanic trench. Volcanic arcs are significant in understanding subduction zone dynamics, magma generation, and the formation of island and continental arcs.
Reference: Stern, R. J. (2002). “Subduction Zones.” Reviews of Geophysics, 40(4), 3-1-3-38.