1. <convention> Used in various speech and writing contexts
(also in lowercase) in roughly its algebraic sense of "unknown
within a set defined by context" (compare N). Thus, the
abbreviation 680x0 stands for 68000, 68010, 68020, 68030 or
68040, and 80x86 stands 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. <graphics> 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.
