Strong's #4525: macger (pronounced mas-gare')
from 5462; a fastener, i.e. (of a person) a smith, (of a thing) a prison:--prison, smith.
Brown-Driver-Briggs Hebrew Lexicon:
1) a shutting up, locksmith, smith, dungeon, enclosure, builder of bulwarks
1a) locksmith, smith
Part of Speech: noun masculine
Relation: from H5462
This word is used 7 times:
2 Kings 24:14: "captives, and all the craftsmen and smiths: none remained, save the poorest sort"
2 Kings 24:16: "even seven thousand, and craftsmen and smiths a thousand, all that were strong and apt"
Psalms 142:7: "Bring my soul out of prison, that I may praise thy name: the righteous"
Isaiah 24:22: "the pit, and shall be shut up in the prison, and after many days shall they be visited."
Isaiah 42:7: "eyes, to bring out the prisoners from the prison, and them that sit in darkness out of the prison"
Jeremiah 24:1: "of Judah, with the carpenters and smiths, from Jerusalem, and had brought them to Babylon."
Jeremiah 29:2: "of Judah and Jerusalem, and the carpenters, and the smiths, were departed from Jerusalem;)"