Other forms: lodes
A lode is a rich vein of metal ore in the rock. Strike a lode, follow the lode, a rich lode.
It is a vein filling a fracture, which is what distinguishes it from ore scattered through the rock, and following one is how hard-rock mining works. The mother lode is the principal vein of a district and has become the standard metaphor for the main source of anything. Note lodestone, a naturally magnetic rock; and lodestar, the star that shows the way.
1nounlodeA rich vein of metal ore in the rock.
“The miners struck a rich lode of silver deep inside the mountain.”
lode is an ore vein.
Lode is a doublet of load, from Old English lad, a way or course. The mining sense keeps the idea of a course to follow, as do lodestar and lodestone.
Old English
lād — way, course, journey
English, today
lode
a doublet of load, which has however become semantically restricted. The now-archaic lode continues the old sense of Old English lād (“way, course, journey”) but by the 19th century survived only dialectally in the sense of “watercourse”, as a technical term in mining, and in the compounds lodestone, lodestar.
Etymology from Wiktionary, CC BY-SA