gold rush is a noun meaning "a sudden happening that brings good fortune (as a sudden opportunity to make money)". It carries 2 recorded senses.
a sudden happening that brings good fortune (as a sudden opportunity to make money)
“the demand for testing has created a boom for those unregulated laboratories where boxes of specimen jars are processed like an assembly line”
a large migration of people to a newly discovered gold field
Definitions, synonyms and semantic relations for gold rush come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.