A* unit

A* unit

[′ā‚stär ‚yü·nət]
(physics)
An atomic standard unit of length, based on the tungsten Kα1 line, approximately 10-11 centimeter; used for measurements of x-ray wavelengths and of crystal dimensions.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.