By Kimberly Amadeo. Definition: Silicon Valley is the center for innovative technology companies. It's located in the are around San Francisco, California.It's home to 2,000 tech companies, the densest concentration in the world. This proximity to suppliers, customers, and cutting edge research gives each a competitive advantage.ilicon Valley Companies. The most well-known Silicon Valley companies include Adobe, Apple, Cisco, eBay, Facebook, Google, Hewlett-Packard, Intel, Intuit, Netflix, Oracle, Salesforce.com, Tesla, Twitter, Yahoo! and Zynga.
Math definition of Substitution: Substitution - A strategy for solving systems of equations that include solving for one variable and using that solution to find the other variable. 1  Subject : Math.  Topic : Algebra 2.
Substitution mutation. Definition. A type of point mutation in which a single nucleotide is substituted with (or exchanged for) a different nucleotide that may result in an altered sequence of amino acid during translation, which may render the newly synthesized protein ineffective.Supplement.xamples of base-pair substitutions: purine substituted with a different purine (A â G) or a pyrimidine for a different pyrimidine (C â T). This type of substitution mutation is transition.