A deviated septum results when cartilage that separates the nostrils is misaligned which may cause partial nasal airway obstruction.
The nasal septum is the wall between the nostrils that separates the two nasal passages; it supports the nose and directs airflow. If your septum deviated, i.e., not straight, it can impair breathing and cause snoring.
The surgery to correct the septum is called septoplasty.