In law and in cultural anthropology, affinity, as distinguished from consanguinity, is kinship by marriage. Anthropology (/ˌænθɹəˈpɒlədʒi/ from Greek grc ἄνθρωπος anthrōpos, "human" -λογία -logia) is the study of Consanguinity (" con- (with sanguine (blood -ity" refers to the property of being from the same Lineage as another person NOTICE TO WOULD-BE ROMEOS ************** It is the relation which each party to a marriage, the husband and wife, bears to the kindred of the other.
A person's affinity kin are called by kin names with '-in-law' added, and the term in-laws is used informally as an umbrella term for them:
Other constructions are occasionally used including the addition of the prefix 'step-', as in 'stepfather-in-law'.
Affinity is usually described as of three kinds. (1) Direct: that relationship which subsists between the husband and his wife's relations by blood or between the wife and the husband's relations by blood. Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products The marriage having made them one person, the blood relations of each are held as related by affinity in the same degree to the one spouse as by consanguinity to the other. But the relation is only with the married parties themselves, and does not bring those in affinity with them in affinity with each other; so a wife's sister has no affinity to her husband's brother. This is secondary affinity. Collateral affinity is the relationship subsisting between the husband and the relations of his wife's relations.
The subject is chiefly important from the matrimonial prohibitions by which the canon law has restricted relations by affinity. Canon law is internal ecclesiastical law governing the Roman Catholic Church, the Eastern Orthodox churches and the Anglican Communion of churches Taking the table of degrees within which marriage is prohibited on account of consanguinity, the rule has been thus extended to affinity, so that wherever relationship to a man himself would be a bar to marriage, relationship to his deceased wife will be the same bar, and vice versa on the husband's decease. See affinity (canon law) for more discussion. In Canon law of the Catholic church, affinity is a relationship arising from the Sexual intercourse of a man and a woman sufficient for the generation of children
Briefly, direct affinity is a bar to marriage. This rule has been founded chiefly on interpretations of the eighteenth chapter of Leviticus. Formerly by law in England, marriages within the degrees of affinity were not absolutely null, but they were liable to be annulled by ecclesiastical process during the lives of both parties; in other words, the incapacity was only a canonical, not a civil, disability. England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland Canon law is internal ecclesiastical law governing the Roman Catholic Church, the Eastern Orthodox churches and the Anglican Communion of churches By the Marriage Act 1835 all marriages of this kind not disputed before the passing of the act were declared absolutely valid, while all subsequent to it were declared null. Year 1835 ( MDCCCXXXV) was a Common year starting on Thursday (link will display the full calendar of the Gregorian Calendar (or a Common This rendered null in England, and not merely voidable, a marriage with a deceased wife's sister or niece.