Mammoth Uncensored Word List:
22 - 18 letter words starting with tr

tracheolaryngotomy transcendentalisms transcendentalists transformationally transilluminations transistorizations transmissibilities transmogrification transportabilities transubstantiating transubstantiation trestrigintillions tresvigintillionth triboelectricities triboluminescences trichloroethylenes trichopathophobics trichotillomaniacs trigintacentillion triphenylphosphine triskaidekaphobias triskaidekaphobics