'Ion Thruster' and 'Ion Engine' should be merged. They are discussing precisely the same material. The distinctions between the two titles are only jargon. In engineering an engine is usually a device that employs a thermodynamic cycle to convert energy from one form to another (e.g. internal combustion engines employ either the Otto Cycle or the Diesel Cycle to convert chemical energy to mechanical energy). Most rocket thrusters (including ion devices) employ very simple open ended thermodynamic conversions with exhaust to the free environment. But this difference is subtle and frankly either title would be fine and both are used in the rocket propulsion community.
'Ion Thruster' and 'Ion Engine' should be merged. They are discussing precisely the same material. The distinctions between the two titles are only jargon. In engineering an engine is usually a device that employs a thermodynamic cycle to convert energy from one form to another (e.g. internal combustion engines employ either the Otto Cycle or the Diesel Cycle to convert chemical energy to mechanical energy). Most rocket thrusters (including ion devices) employ very simple open ended thermodynamic conversions with exhaust to the free environment. But this difference is subtle and frankly either title would be fine and both are used in the rocket propulsion community.