idea

(noun) the content of cognition; the main thing you are thinking about. Synonyms: thought. Examples: "It was not a good idea." "The thought never entered my mind."

(noun) your intention; what you intend to do. Synonyms: mind. Examples: "He had in mind to see his old teacher." "The idea of the game is to capture all the pieces."

(noun) a personal view. Examples: "He has an idea that we don't like him."

(noun) an approximate calculation of quantity or degree or worth. Synonyms: estimate, estimation, approximation. Examples: "An estimate of what it would cost." "A rough idea how long it would take."

(noun) (music) melodic subject of a musical composition. Synonyms: theme, melodic theme, musical theme. Examples: "The theme is announced in the first measures." "The accompanist picked up the idea and elaborated it."