a vague idea in which some confidence is placed
"his impression of her was favorable"
"what are your feelings about the crisis?"
"it strengthened my belief in his sincerity"
"I had a feeling that she was lying"
a general inclusive concept
"The notion that all citizens should have equal access to education is fundamental to our society."
(usually plural) small personal articles or clothing or sewing items
"buttons and needles are notions"
Mental apprehension of whatever may be known, thought, or imagined; idea, concept.
"The sudden notion that they were lost caused them to check their map immediately."
"She had the notion that everyone would be happy to see her arrive early."
Usage: Use notion to describe a vague or casual idea rather than a well-defined plan or established fact. It often implies something uncertain that needs further consideration before becoming a concrete goal.
The word "notion" comes from the Latin nōtiō, which originally meant becoming acquainted with something or taking cognizance of it. It entered English via Old French, carrying forward its sense of an idea or conception derived from knowing.