A bolt for attaching something to rock; (Mining) a tensioned rod passing through a bed of rock and anchoring it to the body of rock behind.
Late 19th century; earliest use found in U.S. Patents.
英汉双解词典包含464360条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。