I'll have a go... I'm sure one of the mods (fraggle?) was thinking of setting up an FAQ... if so feel free to use the info.
Covergence: How the red, green and blue electron guns line up. Only affects CRT based TVs and Projectors. If they aren't lined up correctly, colours/pictures may look odd with blue/red fringes around whites. All three colours need to be correctly aligned. CRT Projectors and especially Rear-projection TVs need to be "converged" on site. TVs are usually alright. Some monitors allow you to adjust convergence.
Deflection... application of magnetic field to position the electron beam correctly to give straight lines etc. Some manufacturers refer to such adjustments as Geometry settings... again to produce an undistorted "bend free" image.
Ghosting... usually only a problem with analogue TV, where reflected signals are picked up by the aerial resulting in one or multiple "ghost" images on either side of the picture ruining the view
Hope this is of some help. Feel free to ask again for clarification. I'm very sleepy this morning and as a consequence I'm not really sure of what I've written