What symbol represents masked air conduction for the left ear?

In audiometric notation, the symbol used to represent masked air conduction for the left ear is a square. Masking is a technique used during hearing tests to ensure that the ear being tested responds solely to the sounds presented, rather than relying on hearing through the other ear. Each symbol in audiograms has specific meanings to indicate different types of hearing thresholds.

Using a square specifically signifies that masking has been applied to the left ear during air conduction testing, alerting the audiologist or hearing aid dispenser to prioritize that ear's response while controlling for the other ear's influence. This helps in accurately determining hearing ability and potential need for hearing devices.