Sentence:  <WSD>Notion</WSD>, again, signifies either the act of apprehending, signalizing, that is, the remarking or taking note of, the various notes, marks, or characters of an object which its qualities afford, or the result of that act. 
Meaning of the word marked with <WSD> tags:  Mental apprehension of whatever may be known, thought, or imagined; idea, concept.