Definition:Point of Inflection

Definition
Let $f$ be a real function defined on an interval $\Bbb I \subseteq \R$.

Let $\xi \in \Bbb I$.

Then $f$ has a point of inflection at $\xi$ $\xi$ is a point on $f$ at which $f$ changes from being concave to convex, or vice versa.

Also known as
A point of inflection can also be seen as inflection point.

An older spelling of inflection is inflexion.

Some sources give the term as a flex.