Concept (noun)

1. An idea or notion.
2. A plan or design.
3. A principle or idea underlying a system or organization.

Origin:

Late 16th century (in the sense "a general idea or notion"): from latin conceptus, past participle of concipere "conceive, take in, understand", from con- "together" + capere "take".

Examples:

1. The concept of time travel has long fascinated science fiction writers.
2. The new car is a concept vehicle that has not yet been put into production.
3. The concept of democracy is based on the idea of political equality.
4. The concept of the project is to create a sustainable community.
5. The restaurant has a concept of using only locally sourced ingredients.