For more on this passage please see the annotations at the bottom of the main page of Macbeth 1.5
How to cite this article:
Mabillard, Amanda. Macbeth Glossary. Shakespeare Online. 20 Aug. 2000. (date when you accessed the information) < http://www.shakespeare-online.com/plays/macbeth/macbethglossary/macbeth1_1/macbethglos_metaphysical.html >.