Have you noticed that we have the word orphan for a child whose parents have died, and widow or widower for a person whose spouse has died, but no word for a parent whose child has died? Author Jen Hutchison would like the word motherling to be used for a mother who has lost a child. It is the title of her book about the tragedy in her life when her own son died. Motherling is an old word meaning ‘precious mother’. Fatherling would also describe a father who has lost a child.
I have previously written about niblings, a word I like, meaning nephews and nieces collectively. It’s one of the words being considered for inclusion in dictionaries, so if you agree, please use it and bandy it around.

Stepmothers need a new name too, because of the association of ‘the wicked stepmother’ from so many fairy tales. The French word is Belle-mère. ‘beautiful mother’. How nice is that!
The Romans had different words for their uncles. Father’s brother was patruus and mother’s brother was avunculus in Latin. There was also amita, father’s sister, and matertera, mother’s sister.

Although the old English word avuncle, meaning your mother’s brother, has become obsolete, the word avuncular has survived, meaning ‘like an uncle’, friendly and kind.
And what about the in-laws? (Sometimes called the ‘outlaws’ when families don’t get on.) Jewish people have the word machatunim, meaning the parents of my son-in-law or daughter-in-law. In English this is sometimes called co-father-in-law or co-mother-in-law, but it’s a bit of a mouthful.
The term in-law dates back to the 14th century and means that, for example, your mother-in-law is your mother in a legal way, though not by blood.
Family members who are related by blood are known as kinship relations, as opposed to affinal relations, (ie having an affinity with) who are related only through marriage.
Cultures differ around the world in their terms for family. In Sudan, for instance, no two types of relatives share the same term. Cousins are named depending on whether they are father’s brother’s children, father’s sister’s children, mother’s brother’s children or mother’s sister’s children.
Completely opposite to that, in Hawaiian culture, siblings and cousins are called by the same term.

Happy Puzzling!