system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: The difference between disease, disorder, and syndrome.
gpt
* disease - a dysfunction in the body, can be used to specifically refer to those caused by an infectious agent
* disorder - a dysfunction in the body, can be used to specifically refer to those **not** caused by an infectious agent
* syndrome - a set of symptoms commonly associated with each other, often used as a placeholder term until the cause is better understood

There is a lot of overlap between these terms for historical reasons.  With a syndrome that has been around for a while, like Down syndrome, that term might continue to be used even if it more properly could be styled a disorder.  Similarly, some disorders are later found to be caused by infections but keep their names.