Are satin and eggshell finish paint the same?

nope, not the same

the goes in this order....
Matte
Eggshell
Satin
Semi-Gloss
Gloss

^^^^

What she said.

Also... 'Flat' is another term used for Matte in case you see a paint can with 'flat' on it.

Also... 'Hi-Gloss' is sometimes used to represent 'Gloss'.

OOOOOOOH I Learned this today at LOWES:

Flat and eggshell can not be scrubbed cleaned, satin and the more 'glossy' you go the easier it will be to clean (scrub) without damaging the paint.... why would you want to scrub? If you have children you'll know the answer. AND the high gloss is used to paint moldings!

They are is now washable flat or matte though -- so that rule doesn't always apply anymore.

Also, the Mr Clean Eraser works wonder on cleaning scuffs and dirt off walls!