1. Used in variousspeech and writing contexts (also in lowercase) in roughly its algebraic sense of "unknown within a set defined by context" (compare N). Thus, the abbreviation 680x0stands for 68000, 68010, 68020, 68030 or 68040, and 80x86stands for Intel 80186, Intel 80286, Intel 80386 or Intel 80486. A Unix hacker might write these as 680[0-4]0 and 80[1-4]86 or 680?0 and 80?86 respectively see glob. 2. s> An alternative name for the X Window system. 3. <storage> A suffix for the speed of a CD-ROM drive relative to standard music CDs (1x). 32x is common in september 1999. [Jargon File] (1999-09-15)