Yes, OED2 gives tourbillon from French in the etymology and as an alternate spelling, but marked as foreign. It also gives two other meanings: "a kind of firework which spins as it rises, describing a spiral" and "a carriage in which the escapement of a watch is fitted so that it revolves round the fourth wheel", the second using the spelling tourbillon in the only quotation.
Yes, OED2 gives tourbillon from French in the etymology and as an alternate spelling, but marked as foreign. It also gives two other meanings: "a kind of firework which spins as it rises, describing a spiral" and "a carriage in which the escapement of a watch is fitted so that it revolves round the fourth wheel", the second using the spelling tourbillon in the only quotation.
I'm guessing related is tourbillon from FRA, which denotes a kind of intricate escapement for timepieces which counters the effects of gravity.
A whirlwind, vortex, eddy or whirlpool.