On the Food network they boil potatoes, but they poach carrots. They poach turkey, but they boil eggs. They sauté’ onions, but they fry eggs in the same pan. Likewise, they fry hash browns, but they sauté’ onions in the same pan before adding the potatoes.
I can go on for days.
Poach equals lower temp liquid. It can be oil or water type liquid. Boil is maximum temp water type liquid only. Blanching is boiling for a short time with the intention of not cooking all of the way through (eg to get skin off or to prepare for preservation by freezing).
Fry and saute are used interchangably all the time. One person’s fried onions is another’s sauted onions. Saute should indicate small pieces turned or tossed in a moderate amout of fat. Fry can be small or large pieces and can have moderate to lots of fat as a cooking medium.
Note that this is how normal people in my region and life use these terms and I make no claim that this is ‘right’ just my experience.