pneumatico-combining form from L. pneumaticus or Gr. πνευµατικός pneumatic: see quots., and pneumatic a. 1, 4.1812–16Playfair Nat.Phil. (1819) I. 257 The syphon is properly a pneumatico-hydraulic machine, the action of water and of air being both necessary to its effect.1816Bentham Chrestom.Wks. 1843 VIII. 90 Pneumatico-Hedonistics, such as have for their objects those more refined classes of pleasures which, passing through one or more of the inlets afforded by the body, find their ultimate seat in the mind.