Syndrome

A syndrome is a constellation of symptoms and signs that appear to be associated and which point towards a definite condition for which the etiology and/or pathogenesis remain to be properly defined. When the cause of a syndrome is understood, it becomes a disease ^1,2.

This meaning is not always adhered to, and some syndromes would perhaps be better called something else, but for historical reasons the word 'syndrome' has become indelibly part of their name, for example AIDS or Down syndrome. 

Unfortunately the label syndrome is sometimes used - and abused - as a label for a hodgepodge of symptoms and signs that are tenuously linked, this happens more often in psychiatry than other specialities.