Word of the Day for Wednesday January 17, 2001:

excursus ik-SKUR-sus, noun:
1. A dissertation that is appended to a work and that contains
a more extended exposition of some important point or topic.
2. A digression.

And the eels not only have a role in the narrator’s story.
.. but receive a 12-page excursus on their genesis and (as
it were) life style.
–William H. Pritchard, “The Body in the River Leem,”
[1]New York Times, March 25, 1984