Monomania \Mon`o*ma"ni*a\, n. [Mono- + mania.] Derangement of the mind in regard of a single subject only; also, such a concentration of interest upon one particular subject or train of ideas to show mental derangement. Syn: Insanity; madness; alienation; aberration; derangement; mania. See {Insanity}. web1913

monomania n : a mania restricted to one thing or idea [syn: {possession}] wn