The story
Developed in 1960-62 by hydraulic engineer Stanley Wade, author Roald Dahl, and neurosurgeon Kenneth Till, after Roald Dahl's son Theo was severely injured.
Etymology from Wiktionary, CC BY-SA 4.0.
Wade-Dahl-Till valve
Today it means: A kind of cerebral shunt using two metal discs, each in a restrictive housing at the end of a tube, opened and closed by the pressure of fluid. Full definition →