from The American Heritage® Dictionary of the English Language, 4th Edition
- A region of western California southeast of San Francisco known for its high-technology design and manufacturing industries.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- proper n. A nickname originally for the region of the San Francisco Bay Area in which there are a high number of industries producing silicon chips and later extended to mean the entire concentration of high-tech businesses in this area.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a region in California to the south of San Francisco that is noted for its concentration of high-technology industries
From "Silicon Valley USA", the title of a series of articles appearing in 1971 in Electronic News by the journalist Don Hoefler, from silicon, the element used by these industries + valley from Santa Clara Valley, the area where many of these industries are located (Wiktionary)