|Also: idée fixe an idea, esp one of an obsessional nature, that is persistently maintained and not subject to change|
|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
fixed idea n.
An often unreasonable idea or feeling that persists despite evidence to the contrary or efforts to ignore it; an obsession. Also called idée fixe.