Konkávna

Konkávna is a term primarily used in geometry and optics. In geometry, a concave shape curves inward, like the inside of a bowl or a cave. A concave polygon is one where at least one interior angle is greater than 180 degrees, meaning a line segment connecting two points inside the polygon can pass outside of it. Conversely, a convex polygon has all interior angles less than 180 degrees, and any line segment connecting two interior points stays entirely within the polygon.

In optics, a concave lens is a diverging lens. It is thinner at the center than at the edges and causes parallel rays of light to diverge, making them appear to originate from a focal point on the same side of the lens as the incoming light. This property is utilized in eyeglasses to correct myopia (nearsightedness) by spreading out light before it enters the eye. Similarly, a concave mirror curves inward, like the inside of a spoon. It converges parallel light rays to a focal point in front of the mirror. Concave mirrors are used in telescopes and headlights. The term "konkávna" shares roots with the English "concave," both deriving from Latin words related to hollowing out or curving inward.