Definitions for "Second-degree relative"
Keywords:  aunt, uncle, niece, nephew, grandparent
Any relative who is two meioses away from a particular individual in a pedigree; a relative with whom one quarter of an individual's genes is shared (i.e., grandparent, grandchild, uncle, aunt, nephew, niece, half-sibling)
SDR. An individual's relative who is an aunt, uncle, grandparent, grandchild, niece, nephew, or half-sibling.
grandparent, aunt, uncle or grandchild.