What does the medical abbreviation ARDS mean?

Acute Respiratory Distress Syndrome.

It is essentially when the lungs begin to "harden", not letting oxygen pass through into the bloodstream.
Adult Respiratory Distress Syndrome
The abbreviation ARDS has several meaning in the healthcare field.

Examples include:

Acid-Related Disorders

Acquired Respiratory Distress Syndrome

Acute Respiratory Disease Syndrome

Adult Respiratory Distress Syndrome

Alcohol-Related Disorders

Aortic Ring Diameters

Antirheumatic Drugs