The transition area between gluteal cleft and buttock. An area that is not definitively crack or cheek.
A pubic louse in the in the butt-crack of murdered prostitute lying naked, face down, in the middle of the street at dusk would observe the sun to set over the cleftal horizon.
Someone or something that bites your ankles.
To a postman, an ankle biter is often known as a dog.
To an adult, an ankle biter may be a toddler.
To hikers, an ankle biter is sometimes a tick.
And so on.
When a man will search for hours to find something that is laying out in the open on a table. Items are often easily found by a women.
Man: "I have been searching for hours for keys."
Woman: "You mean the ones sitting there on the coffee table?"
Man: "Where?"
Woman: "Right there in the middle of that table."
Man: "oh, must have been Male Pattern Blindness"