Definition: LOD stands for "logarithm of the odds." In genetics, the LOD score is a statistical estimate of whether two genes, or a gene and a disease gene, are likely to be located near each other on a chromosome and are therefore likely to be inherited. A LOD score of 3 or higher is generally understood to mean that two genes are located close to each other on the chromosome. In terms of significance, a LOD score of 3 means the odds are a thousand to one that the two genes are linked, and therefore inherited together.