1.NounA component in a device, or a point in a network, that, if it were to fail, would cause the entire device or network to fail (normally eliminated by adding redundancy).
"The Jesus nut got its name because it is a single point of failure — if it goes, there's nothing you can do but pray."
2.NounA minor mistake that creates a chain reaction.
"The intact twine in Dylan's beef Wellington was a single point of failure."