Theme
Part of speech: noun
Definition: a subject of a talk or an artistic piece; a topic. a recurring idea; a motif. the main melody of a piece of music, especially one that is the source of variations. The collection of color schemes, sounds, artwork etc., that "skin" an environment towards a particular motif. stem of a word thematic relation of a noun phrase to a verb theta role in generative grammar and government and binding theory. topic, what is being talked about, as opposed to rheme
Example sentence: Most of my albums have a concept. They all have some kind of theme, some kind of feeling. I really take pride in that.
Idea
Part of speech: noun
Definition: The transcript, image, or picture of a visible object that is formed by the mind; also, a similar image of any object whatever, whether sensible or spiritual.That which exists in the mind as the result of mental activity; a thought or a conceptSomeone's opinion, belief or conviction that is accepted as trueAn intuitive notion; a feeling or hunchA plan or scheme for doing something, or an intentionA musical theme or melodic subject
Example sentence: I'm completely in favor of the separation of Church and State. My idea is that these two institutions screw us up enough on their own, so both of them together is certain death.