Kin; relative. The connection of two individuals, or their situation with respect to each other, who are associated, either by law, agreement, or kinship in a social status or union for purposes of domestic life, such as PARENT AND CHILD or HUSBAND AND WIFE.
The doctrine of relation is the principle by which an act performed at one time is deemed, through a legal fiction, to have been performed at a prior time. For example, in the conveyance of real property, the final proceeding that completes the transfer of property is considered, for certain purposes, to have become effective by relation as of the day when the first proceeding took place. Relation, in essence, is the legal term for retroactive effect.