Azusa (əzōˈsə) [key], city (1990 pop. 41,333), Los Angeles co., S Calif., in the San Gabriel valley; inc. 1898. It is a residential and industrial city in a citrus-fruit growing area. Its varied manufactures include aerospace and aircraft-navigation equipment, baggage-handling vehicles, industrial controls, electronic and transportation equipment, fabricated metal products, machinery, furniture, chemicals, and optical instruments. Azusa Pacific College is in the city.