Side slam backbreaker is a type of Backbreaker.
The wrestler firsts stands side-to-side and slightly behind with the opponent, facing in the opposite direction before next reaching around the opponent's torso with one arm across the opponent's chest and under both arms, lifting him or her in the air as though the wrestler is about to deliver a side slam. However, as the wrestler brings the opponent back down to the mat the attacking wrestler kneels, slamming the opponent's back across his/her extended knee.
A swinging side slam variation sees the attacking wrestler first lift the opponent horizontally across their chest before swinging them to their side and dropping the opponent back first on their knee. A spinning side slam variation sees the attacking wrestler catch an oncoming opponent and spin them around 180° before dropping them back first onto their knee.