The word "parabolic" relates to a shape or curve that is like a U or bowl shape. It can also refer to anything resembling or relating to a parabola, which is a mathematical curve. Full definition
Numerical Study on Heat Transfer Enhancement in a Receiver Tube of Parabolic Trough Solar Collector with Dimples, Protrusions and Helical Fins (solarpaces.org)
Experimental Study on Heat Transfer with Molten Salt in Parabolic Trough Solar Collector System (solarpaces.org)
* This strategy only works well during bubbles (i.e. when the market is going parabolic on a log scale). (bullmarkets.co)