An integer that identifies an open file within a process. This number is obtained as a result of opening a file. Operations which read, write, OR close a file would take the file descriptOR as an input parameter. In many operating system implementations, file descriptORs are small integers which index a table of open files. In Unix, file descriptORs 0, 1 and 2 cORrespond to the standard input, standard output and standard errOR files respectively. See file descriptOR leak. (1998-02-06)