Ascension is the expansion of awareness.
Why is it called Ascension? Because our overall vibration becomes higher, and we are able to tap into and work within higher "dimensions".
Do we take our bodies with us? Our physical body is a key element of functioning within a solid 3D environment. When we start moving into a higher vibration in our lives, our bodies also follow suit. This is why, often, foods and chemicals that we were able to absorb our entire lives, will make us sick for a while (the time it takes for the physical body to adapt to the new vibrational environment).
By detoxing our bodies and keeping them sugar and other toxin free, we help it, help us, in our expansion of awareness.
Of course, "Ascension" is used by others to mean all sorts of things, but within this website, the above definition is what it means when it is mentioned.