ABCDEFGHIJKLMNOPQRSTUVWXYZ Definition of Common Ratio more ... The amount we multiply by each time in a geometric sequence. Example: 1, 2, 4, 8, 16, 32, 64, 128, 256, ... Each number is 2 times the number before it, so the Common Ratio is 2 See: Geometric Sequence Number Sequences - Square, Cube and Fibonacci