The title given for the takeoff whenever both feet leave the ground at the same time. Used most commonly in vert spin kicks, but also used as a tag whenever a trick which is usually performed in gainer or other one-footed takeoff happens off of two feet. "Pop" is also used on this site to refer to a transition whenever the landing of the first trick essentially IS the takeoff of the second trick (unless replaced by another transition such as swing thru or missleg). This means that wherever and however the landing happens the takeoff happens from that exact place.