"Interbank volumes drop in pre-holiday trading," MTI- Econews, October 22, 1998
(also `logical Friday') The last day before an extended weekend, if that day is not a `real' Friday. For example, the U.S. holiday Thanksgiving is always on a Thursday. The next day is often also a holiday or taken as an extra day off, in which case Wednesday of that week is a virtual Friday (and Thursday is a virtual Saturday, as is Friday). There are also virtual Mondays that are actually Tuesdays, after the three-day weekends associated with many national holidays in the U.S.
Eric Raymond, "The New Hacker's Dictionary," MIT Press, September, 1991