Twists: This is a general term for the Aerial Twist (atwist) and Butterfly Twist (btwist). The Butterfly (aka bkick) is one of the first tricks many trickers learn, and can be found in several different genres of movement including traditional martial arts, gymnastics, dance, and figure skating. This family is generally initiated from several stances, including inside and frontside, and is swung into from a mega landing. Its defining characteristic is its flat spin, with the chest facing down, approximately parallel to the ground. Within tricking, the Aerial is most often performed as a fully inverted Butterfly, and can be seen as closely related. Similarly, the twisted variations of the Butterfly and Aerial are also seen as closely related, despite their differences in inversion. This is in part due to the ambiguity found when partially inverting both the twisted and untwisted butterfly variations, or when under-inverting the twisted and untwisted aerial variations.
There is a growing belief in the community that a true atwist should takeoff sideways, like a fully inverted butterfly. The thought is that the more common forward takeoff, similar to a traditional gymnastics aerial, is actually a webster-twist, and the two should be understood as separate. This concept is still relatively new and controversial, and no consensus has been made. It discussed further, albeit breifly, on the webster page linked below. If necessary, this page and the webster page will be updated accordingly.