There are some places where men and women are segregated — for example public toilets and public swimming pool changing areas.
By this I mean, for example, that there are "Men's toilets" and "Ladies' toilets".
However, in some more cosmopolitan swimming baths, and other places, there are such things as unisex changing areas, or unisex toilets.
From my understanding uni- implies one, as in universe, unilateral or unicycle.
However when it comes to unisex, this means both sexes, so applies to two things.
How does uni- mean one in unisex? Does it mean one?