Broadside battles were a type of warfare employed during naval battles, both in space and at maritime levels. The battle involved two ships on opposing sides flying across from each other and then each ship firing its main cannons towards the other side of the ship until one of the vessels, or even both, sustained sufficient damage for it/them to no longer be functional.
During the Battle of Coruscant nearing the end of the Clone Wars, the Venator-class Star Destroyer Guarlara entered a broadside battle against the modified Providence-class carrier/destroyer Invisible Hand, the flagship of the Separatist forces, an action that nearly resulted in Palpatine, Anakin Skywalker, and Obi-Wan Kenobi's deaths due to the Invisible Hand sustaining heavy and irreparable damage from the battle.
During the Battle of Endor, several ships in both the Rebel fleet and Death Squadron entered several broadside battles; the former doing so in order to delay the Death Star II's superlaser firing protocols (as the Imperials are unwilling to risk hitting any of their own ships with the superlaser), an action that, due to the unprecedented nature of the circumstances of the broadside battles, was described as "chaotic."
During the Battle of Orinda, the Executor-class Star Dreadnoughts Lusankya and the Reaper exchanged a broadside battle.
- The Essential Guide to Warfare