noun / verb
curve
KURV/kɜːrv/
A line or path bending smoothly from a straight direction.
The river curves gently through the fields in one continuous bend.

Etymology
The verb meaning “to bend” supplied the noun for a line that bends continuously without angles. That image also describes a smoothly bending surface or path.
In context
a pillow here in your waistline to support this curve. Otherwise, as you sleep, this part of your spine, gravity will pull it down towards the bed, causing a side bending
More examples
- The road follows a gentle curve around the hill.
- The graph's curve rises as the water warms.
- The pitcher throws a curve that drops near the plate.
Forms
curve · curves · curved · curving
curvature noun — The degree to which something bends.