An inflection point, in a general sense, is a decisive moment in the course of some entity, event or situation that marks the start of significant change.
The concept of the inflection point comes from mathematics. In that context, an inflection point is a point on a convex (upward) curve where it becomes concave (downward) or vice versa.
An inflection points is often identified in retrospect as a moment in time when an event led to significant improvement, deterioration or disruption. By definition, a disruptive technology marks an inflection point. The personal computer (PC), for example, displaced the typewriter and forever changed the way we work and communicate.
Cell phones caused an inflection point in the telecom industry; then smartphones in turn disrupted the mobile industry and personal computing. Because of the available apps, smartphones also disrupted: PDAs, pocket cameras, MP3 players, calculators and GPS devices, among other things.
In the early 1990s, Andy Grove of Intel coined the term strategic inflection point to describe a point at which a continuation of the status quo would lead to certain failure. On a graph, that inflection point could be depicted by a line with an upward trajectory beginning to curve downward.