Plane (πλάνη) is a feminine noun meaning a wandering, error, deception, or delusion. It is the noun form related to the verb planao (G4105). It describes the state or condition of being led astray — the error itself, whether intellectual, moral, or spiritual. It can refer to the deceptive influence that causes the wandering or to the resulting state of being in error.
In the New Testament, plane is used to describe both the act of deception and the doctrinal or moral error that results from it. Paul warns in 2 Thessalonians 2:11 that God sends a "powerful delusion" (plane) upon those who refuse to love the truth. In Romans 1:27, it describes the error of turning from God's design. Jude 11 warns of the error of Balaam. The word carries eschatological weight — the last days will be characterized by widespread plane (deception). The antidote Scripture provides is adherence to truth: "You will know the truth, and the truth will set you free" (John 8:32). Every instance of plane in the NT reinforces the urgent need for believers to be rooted in God's Word to resist the spirit of error (1 John 4:6).