Obsession (n) - ...the desire to have a place, even if only in the mind.... (Harald Szeemann)

1. Compulsive preoccupation with a fixed idea or an unwanted feeling or emotion, often accompanied by symptoms of anxiety.

2. A compulsive, often unreasonable idea or emotion.

1. (Psychiatry) Psychiatry a persistent idea or impulse that continually forces its way into consciousness, often associated with anxiety and mental illness

2. a persistent preoccupation, idea, or feeling

3. the act of obsessing or the state of being obsessed

1.

the domination of one's thoughts or feelings by a persistent idea, image, desire,
2.

the idea, image, desire, feeling, itself