hearing loss which shows up as a relatively flat (but lowered) line on your audiogram is called a "flat loss".
It means that your hearing is diminished (you hear less volume) in all frequencies.
A flat loss is relatively uncommon and is often caused by a conductive problem rather than a sensorineural problem.
Other relatively rare types of losses include:
All of these types of losses are much less common than the most common type of loss, a high frequency loss, normally called a ski slope loss.