Definition of "nibling"
nibling
noun
plural niblings
(originally chiefly anthropology, often in the plural) Used especially as a gender-neutral term: the child of one's sibling or sibling-in-law; one's nephew or niece.
Quotations
Aunts and uncles are concerned with the education of their niblings and may play a minor role in the ultimate arrangement of a marriage for the nibling.
1967, Ben J. Wallace, Gaddang Agriculture: The Focus of Ecological and Cultural Change (unpublished Ph.D. dissertation), Madison, Wis.: University of Wisconsin
In the following line we find Q1P2; that is, child of a parent of a parent; this is the relation that nuncles (aunts or uncles) bear to niblings (nieces or nephews).
1974, Roger W. Shuy, Charles-James N. Bailey, editors, Towards Tomorrow’s Linguistics, Washington, D.C.: Georgetown University Press, page 125
She [Viola Edmundson Garfield] was close to her family, particularly her younger “siblings and niblings.”
1988, Jay Miller, “Viola Edmundson Garfield”, in Ute Gacs, Aisha Khan, Jerrie McIntyre, Ruth Weinberg, editors, Women Anthropologists: Selected Biographies, Illini Books edition, Urbana, Chicago, Ill.: University of Illinois Press, published 1989, page 112
Kin selection was strongest for choices between sibling and friend, decreasing across sibling vs. nibling, nibling vs. friend, and nibling vs. cousin, [...]
1998 May, Daniel J. Kruger, “Male Relatives Benefit More from Kin Selecting Tendencies Enhancing Social Status”, in Daniel J. Kruger, PhD, University of Michigan, archived from the original on 17 June 2019
Most distinctive of the system, therefore, were the two terms for parental siblings and for niblings, which occurred only among the Salish and neighboring Southern Nootkans.
1999, Jay Miller, “Body”, in Lushootseed Culture and the Shamanic Odyssey: An Anchored Radiance, Lincoln, Neb., London: University of Nebraska Press, page 127
Cousins are informally referred to by the same terms used for siblings, but officially one has an aunt/uncle-nibling relationship with one's cousins.
2005 February, N. J. Enfield, “The Body as a Cognitive Artifact in Kinship Representations: Hand Gesture Diagrams by Speakers of Lao”, in Current Anthropology, volume 46, number 1, Chicago, Ill.: University of Chicago Press, pages 51–81; quoted in N. J. Enfield, “Diagramming”, in The Anatomy of Meaning: Speech, Gesture, and Composite Utterances (Language, Culture, and Cognition; 8), Cambridge, Cambridgeshire: Cambridge University Press, 2009, part II (Illustrative Components of Moves), page 161