1. alum rock - Noun
2. Alum rock - Proper noun
alum rock (uncountable)
The mineral alunite.
A census-designated place in Santa Clara County, California, United States.
A historical community in Clarion County, Pennsylvania, United States.
An inner suburb of Birmingham, West Midlands, England (OS grid ref SP1287).
Source: en.wiktionary.orgThese include many high-tech workers from East and South Asia, Eastern European immigrants, as well as poorer immigrants from Latin America, many of whom can be found in the large, multi-generational barrio Alum Rock district. Source: Internet