Definition: Fibonacci numbers

A series of whole numbers in which each number is the sum of the two preceding ones: 1, 1, 2, 3, 5, 8, 13, etc. Fibonacci numbers are used in a variety of algorithms, including stock market analysis. They are used to speed up binary searches, whereby the search is divided into the two previous numbers. For example, 13 items are divided into 8 and 5 items, and 8 items are divided into 5 and 3.