A karass of only two
people, who are so bound together that even their
children cannot invade their union. From Kurt Vonnegut's "Cat's Cradle." (A karass is a group of
people bound together, often without externally discernable ties.)
From "Cat's Cradle":
“They were lovebirds. They entertained each other endlessly with little gifts: sights worth seeing out the plane
window, amusing or instructive bits from things they read, random recollections of times
gone by. They were, I think, a
flawless example of what Bokonon calls a duprass, which is a karass composed of only two persons.”