notion

Some common synonyms of notion are conception, concept, idea, impression, and thought. While all these words mean "what exists in the mind as a representation (as of something comprehended) or as a formulation (as of a plan)," notion suggests an idea not much resolved by analysis or reflection and may suggest the capricious or accidental.

The words concept and notion can be used in similar contexts, but concept may apply to the idea formed by consideration of instances of a species or genus or, more broadly, to any idea of what a thing ought to be.

Conception is often interchangeable with concept; it may stress the process of imagining or formulating rather than the result.

While in some cases nearly identical to notion, idea may apply to a mental image or formulation of something seen or known or imagined, to a pure abstraction, or to something assumed or vaguely sensed.

The words impression and notion are synonyms, but do differ in nuance. Specifically, impression applies to an idea or notion resulting immediately from some stimulation of the senses.

In some situations, the words thought and notion are roughly equivalent. However, thought is likely to suggest the result of reflecting, reasoning, or meditating rather than of imagining.