But 'ball', like 'marriage' only NEEDS explaining and naming in certain circumstances.

"Come to the picnic and bring a 'ball'." needs a little clarification.
"No, I didn't mean a medicine ball!"

Marriage needs qualification only when someone NEEDS to know that you are..or are not.. a specific type of partnership.
"Have you even been married?" can be a simple question related to legal questions about taxes.... it need not refer to same-sex or 'standard'. It might just precede "list your co-filers on this form."

The **concept** of "legally committed for relationship and legal purposes" simply does not require specification of the sexes involved.