Fibonacci series[fē′bə nä′c̸hē]
Fibonacci series definition by Webster's New World
a sequence of integers in which each integer () after the second is the sum of the two preceding integers; specif., the series 1, 1, 2, 3, 5, 8, 13, . . .
Origin: after L. Fibonacci, 13th-c. It. mathematician, who developed it