Silicon Valley is the nickname for the bay area in-between San Fransisco and San Jose. It got it’s name from the fact that computer company startups (who used, created, and innovated silicon “computer chips”) were centered in the Santa Clara Valley in San Jose.

Today the whole tech industry is sometimes referred to as Silicon Valley, but more often it refers to the tech culture of the whole San Fran / San Jose bay area (where venture capital and computer tech companies are still prevalent).