Artificial horizon - "horizon bar" or "symbolic airplane adjust"
Instrument parallax has to do with viewing position of the pilot compared to the instrument. You adjust the symbolic airplane to the horizon bar on the outside of the instrument, not the part that moves, so you don't have to wait for it to spin up or find flat ground. I do it as part of my pre-start instrument checks, after adjusting my seat.
All mechanical AIs should have an adjustment mechanism, but many modern ones are digital, with a flat screen. You can't have parallax error with a screen because there is no distance between the needles and the reference measurements.