Solemnity: pompe funebri
In this expression, ‘pompa’ comes from Latin pompa, in turn from Ancient Greek (Dorian , verb , I send, I escort), with the meaning of ‘act of sending, of escorting’, hence ‘procession’.
Technology: pompa idraulica
The Italian ‘pompa’ as hydraulic machine comes from French pompe: possible sources are the Middle Dutch pompe with the meaning of water conduit, pipe (XV century), and the Middle Low German pumpe with the meaning of (hydraulic) pump. From 1300 to 1600, during the Hanseatic period, Middle Low German was the lingua franca in Northern Europe. This suggests a nautical origin among North Sea sailors, but the origin of pumpe is almost unknown. Bilge (‘sentina’ in Italian) pumps (made by wood-block, bronze and lead) were mounted on ships since Greek and Roman ancient times .
A synonym of ‘pompa’ as hydraulic machine is ‘tromba’ , from Old High German (from 750 to 1050) trumpa, trumpen with the meaning of musical instrument (English trumpet) and pipe, of uncertain origin. The same suffix -umpe(n) and close meaning may suggest commonality in their etymology. Imitative origin of both terms is suggested by some scholars.
The gross term ‘pompino’, meaning fellatio (from Latin fellare, to suck, from the Proto-Indo-European root *dhe, to suck) seems rather recent (early XX century), and no doubt that it comes from the artifact ‘pompa’. A close vulgar term (XIII century), this time coming from ‘tromba’, is ‘trombare’ meaning ‘to copulate’. Both terms belong to the reach vocabulary of sexual metaphors.
A similar metaphor from hydraulic machinery can be found in the obsolete vulgar English ‘pump (noun)’ with the meaning of ‘vagina’ and ‘to pump (verb)’ meaning ‘to copulate’. They appear in two verses of the popular song ‘Ge, ho, Dobbin or the Waggoner’ collected with other ones in . The metaphor is completed by ‘sucker’ (a synonym of ‘piston’, the movable part of a displacement pump) meaning ‘penis’, ibidem. ‘Waggoner’ is the Italian ‘carrettiere’. ‘Ge, ho, Dobbin’ is the command ‘giddy up’ to a horse (‘Dobbin’).
 M. Dogliotti and L. Rosiello (eds), Il nuovo Zingarelli. Vocabolario della lingua italiana, Zanichelli, Bologna, 1984.
 Anonymous, The tulip, or, the musical companion: being a collection of the politest songs now in vogue. J. Towers, near Air-Street, Piccadilly, 1750 (?).
 J.P. Oleson, The final word on Roman wooden pumping machinery, Journal of Roman Archaelogy, Vol. 28, 2015, pp. 707-708.