TIL: couplehood

As in

Fisher, like many other experts, attributes the sex decline to a decline in couplehood among young people.
...
About 60 percent of adults under age 35 now live without a spouse or a partner. One in three adults in this age range live with their parents, making that the most common living arrangement for the cohort.

https://www.theatlantic.com/magazine/archive/2018/12/the-sex-recession/573949/

A similar concept is used for describing quantum processes:



from Coecke & Kissinger, Picturing Quantum Processes, 2017