plug-and-feather hole

plug-and-feather hole

[¦pləg ən ′feth·ər ‚hōl]
(engineering)
A hole drilled in quarries for the purpose of splitting a block of stone by the plug-and-feather method.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.