Steering alignment = adjusting the toe angles of the front wheels so that they point in the right direction when the steering wheel is straight. Best done with driver sitting in car holding wheel straight ahead.
Geo = adjust all the angles on the steering and suspension (do this after changing ride height, after a bump and for a new car as they are never right). Also best done with driver in car, holding wheel straight ahead.
Front and rear camber (how much the wheels lean in).
Front and rear toe (how much wheels point out or in)
Front caster (how much the wheel leans back).
Rear bump steer (how much the rear wheels toe in/out when the suspension compresses).
Typically people just set the first two of these, as the caster is factory set to be something vaguely sensible and is a pain to adjust, and bump steer requires extra equipment. So normally when they say "geo" they mean toe+camber.
The first two (camber and toe) make a big difference to the handling of the car, so well worth getting them all set - but then you need to decide what to get them set to!
If it's a road-only car, then the factory standard settings are going to be fine (but don't for a minute think that cars leaving the factory have those settings
).
For track use you might want more some negative camber at the front.
For extensive track use, you'll want your own personal setup, honed over hours and hours of testing (or just copy someone else's who is quicker than you).
Cheers,
Robin
