Y2K
Acronym for the year 2000 (“Year Two Thousand”). Most often used in the context of the “Y2K bug” on the occasion of the computer transition to the year 2000. Some applications running at the time stored the year in two digits and therefore threatened to return to 1900 (00 in two digits) instead of 2000. This was likely to cause many inconsistencies in processing and databases. There will ultimately be no major incident, at the cost of considerable sums spent to review (or replace) the applications concerned (Wikipedia speaks of several hundred billion dollars devoted to the task throughout the world).
The first of January of each year is now a holiday for all information system consultants in the world, in (moved) memory of this market worth “a few” hundred billion dollars.