Real Dictionary

-mania in American English
a (specified) type of mental disorder characterized by an abnormal preoccupation, compulsion, etc.
combining form: a combining form of mania (megalomania); extended to mean “enthusiasm, often of an extreme and transient nature,” for that specified by the initial element (bibliomania)

-mania in British English
combining form in countable noun: indicating extreme desire or pleasure of a specified kind or an abnormal excitement aroused by something

mania
If you say that a person or group has a mania for something, you mean that they enjoy it very much or spend a lot of time on it.

mania in American English
wild or violent mental disorder; specif., the manic phase of bipolar affective disorder, characterized generally by abnormal excitability, exaggerated feelings of well-being, flight of ideas, excessive activity, etc.
noun: an ancient Roman goddess of the dead
noun: excessive excitement or enthusiasm; craze

mania in British English
noun: a disorder characterized by great excitement and occasionally violent behaviour