- 1. or x or Xthe usual symbol for power as a unit of magnification. More generally, × or x is used with its mathematical meaning, "times," to indicate that a measurement is a multiple of some standard or reference measurement. For example, an image marked 200× is shown at 200 times actual size (that is, distances are 200 times actual size), and a 10x CD-ROM drive is one capable of transferring data 10 times faster than the "normal" or standard speed.2. see diameter
Dictionary of units of measurement. 2015.