The relation of persons by blood, in distinction from affinity or relation by marriage; blood relationship; as, lineal consanguinity; collateral consanguinity.

Being closely genetically related. Generally defines first-degree blood relatives.

The following is quoted from Webster's New Collegiate Dictionary: Blood relationship; descent from a common ancestor; - ... The degrees of lineal consanguinity are reckoned as one degree for each person in the line of descent, exclusive of him from whom the computation begins. A chart, copied from a previous version of Websters dictionary, is available. Click here to display.

Relationship between two individuals with a common ancestor, for example, cousins (see Genetics Fact Sheet 26: When Parents are Relatives: Consanguinity).