The story
Blend of dynamic + focal. Genericised from the product name "Dynafocal Suspensions" from Lord Corporation in 1939, earlier called "Dynamic Suspensions".
Etymology from Wiktionary, CC BY-SA 4.0.
dynafocal
Today it means: Of or pertaining to a particular kind of aircraft engine mount that gives directional support to a radial engine to reduce vibration. Full definition →