idea

noun

• An abstract archetype of a given thing, compared to which real-life examples are seen as imperfect approximations; pure essence, as opposed to actual examples.
• The conception of someone or something as representing a perfect example; an ideal.
• The form or shape of something; a quintessential aspect or characteristic.
• An image of an object that is formed in the mind or recalled by the memory.

  "The mere idea of you is enough to excite me."

• More generally, any result of mental activity; a thought, a notion; a way of thinking.
• A conception in the mind of something to be done; a plan for doing something, an intention.

  "I have an idea of how we might escape."

• A purposeful aim or goal; intent

  "Yeah, that's the idea."

• A vague or fanciful notion; a feeling or hunch; an impression.

  "He had the wild idea that if he leant forward a little, he might be able to touch the mountain-top."

• A musical theme or melodic subject.