sixty-nine

The story

1. French · calque ofsoixante-neuf
2. English todaysixty-nine

Calque of French soixante-neuf, from the rotational symmetry of the numeral 69 — if rotated a half-turn (by 180°), the numeral remains the same, and a couple both giving oral sex at once have, in principle, a similar rotational symmetry.

Words from the same roots