Coupler of organ—generally a pedal coupler. So tirasse du positif, du récit, du grande orgue, mean respectively Choir to Pedal, Swell to Pedal, Great to Pedal. These may be abbreviated to Tir. P., Tir. R., and Tir. G.O. Tirasse G.P.R. means that all 3 couplers are to be used.