Why is $AIDS$ considered to be a 'Syndrome' and not a disease?

(N/A) $AIDS$ stands for Acquired Immuno Deficiency Syndrome.
$AIDS$ is caused by the $HIV$ virus, which enters the body through sexual contact, blood transfusion, or other means.
Once inside, the virus spreads to the lymph nodes throughout the body and severely damages the immune system.
Because the immune system is compromised, the body can no longer fight off minor infections.
Consequently, simple infections like a common cold can escalate into pneumonia, or a minor gut infection can lead to severe diarrhoea and blood loss.
Since $AIDS$ does not present a single specific set of symptoms but rather manifests as a complex collection of various diseases and symptoms resulting from a weakened immune system, it is classified as a 'Syndrome' rather than a single disease.