n. The main, central lode of a natural resource, near which smaller deposits of the same ore etc. exist.
n. The main prize, best cut or pick etc. by far, dwarfing all others.
Word Usage
"US intelligence network aims to put heat on al-Qa'ida US intelligence will seek to achieve in the coming weeks "information dominance" over the al-Qa'ida network - taking advantage of what officials have called a "motherlode" of data found at Osama bin Laden's compound in Abbottabad."