Is there a difference?

This might be a silly question but, is eyeshadow primer and eyeshadow base the same thing? I own urban decay eyeshadow primer (works like a charm) and bought NYX eyeshadow base thinking it would work the same. Is it? I've noticed it still creases a tiny bit after long wear so I'm unsure now. 
​And, what eyeshadow primer do you ladies recommend? :) I wear eyeshadow & eyeliner a lot ??