headstock definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a bearing or support for a revolving or moving part of a machine; specif., the part of a lathe supporting the spindle
headstock definition by American Heritage Dictionary
A nonmoving part of a machine or power tool that supports a revolving part, such as the spindle of a lathe.