I cannot by any effort of thought conceive the abstract idea above described.

First, The abstract ideas they stand for are made by the understanding.

Then he moved on to more abstract ideas and to forms based less literally in popular culture.

That I had been born there was an abstract idea.

Often it is used to represent the whole of an abstract idea.

He had no abstract ideas about justice and fair play.

He was noted for his success in selling abstract ideas rather than products.

The school theme, in the end, served as an abstract idea.

Personal - an intellectual being and not an abstract idea.

Death is kind of an abstract idea for very young children, who think that the person will wake up or somehow come back to them.