Wasn't renamed, but if your asking which is better, I'd say advancements, as they can be easily customized without mods. Even with mods, it cuts out the middleman and can replace questing book mods and work in its place, take a look at sevtech ages, a wonderful example of this. Achievments were a branch of, well, achievements, they did nothing but say hey look you did a cool thing, and help guide people who had no clue what they were doing. Meanwhile, advancements can help you unlock new recipes, advance, and do cool things with them. Don't think they were renamed though.

Exactly what partykid4 said. They are not the same. For example: You get an advancement for making your first pickaxe and you can get a achievement if you knock back a Ghast's fireball.

They weren't "renamed", Advancements are a completely different system.