notion

1. Mental apprehension of whatever may be known, thought, or imagined; idea, concept.
2. A sentiment; an opinion.
3. (obsolete) Sense; mind.
4. (colloquial) An invention; an ingenious device; a knickknack.
5. Any small article used in sewing and haberdashery, either for attachment to garments or as a tool, such as a button, zipper, or thimble.
6. (colloquial) Inclination; intention; predisposition; disposition.