The Collaborative International Dictionary
millennium bug \mil*len"ni*um bug`\ (m[i^]l*l[e^]n"n[i^]*[u^]m b[u^]g`), n. (Computers) An error in the coding of certain computer programs which store the year component of the date as two digits, assuming that the first two digits are 19, rather than as a complete number of four digits; when such programs are used after January 1, 2000, the date may be misinterpreted, causing serious errors or total failure of the program; -- called also year 2000 bug, year 2000 problem and Y2K bug.
Note: In the several years leading up to the year 2000, large corporations and other users of computers in total spent many billions of dollars correcting this error in the programs they use.
year 2000 bug \year 2000 bug\, year 2000 problem \year 2000 problem\, n. (Computers) an error in the coding of certain computer programs in which the year portion of dates was represented by only two decimal digits, assuming that the first two digits are ``19''. In such a program the the year 1975 is represented as ``75''. This was a common practise in computer programming even into the 1990's, as many programmers failed to consider that their programs would be used after the year 1999. Thus, with such a program, a person born in 2000 would be considered as 101 years old in 2001; many different serious problems, as various as the programs, could be caused by such an error.
Note: In 1998 many programs with the year 2000 bug were still not corrected, and it is not clear how many programs will retain the bug when the year 2000 arrives. Tune in then.
Syn: millemium bug, Y2K bug, Y2K problem. [PJC]