Epiphenomenon

Epiphenomemon has two distinct menaings.

• 1) A secondary phenomenon that results from and accompanies another.
• 2) Pathology. An additional symptom or condition or symptom in the course of a disease, not necessarily connected with the disease.

In the first sense, it is a side-effect or by-product, that is, there is a causal relationship between the secondary phenomenon and the first.

In the second sense, the medical meaning, there is no such relationship. A doctor might ask a patient whom he is treating for a disease ," Have you noticed any new epiphenomena?"

(Well, mine do!!!)

Source: The American Heritage Dictionary of the English Language. 3rd ed.