The state of being tangent, or touching something at only one point.
Tangency is a math word that means two things are touching at only one point.
Examples:
The tangency of the circle and the line is at one point.
The tangency of the ball and the ground is where they touch.
At the tangency, the circle and the line are together.
The tangency of the cat and the table is funny.
The tangency of the sun and the moon is at one point in the sky.
The tangency of the car and the road is where they meet.