Mammoth Uncensored Word List:
80 words ending with s, 21 letters long

acetylcholinesterases adrenocorticosteroids adrenocorticotrophins anatomicophysiologies anthropomorphizations antiauthoritarianisms antienvironmentalists antiinstitutionalists buckminsterfullerenes chronostratigraphists colpoperineorrhaphies compartmentalisations compartmentalizations contemporaneousnesses counterdemonstrations counterproductiveness disadvantageousnesses duoquinquagintillions electrocardiographies electroencephalograms electroretinographies episioelytrorrhaphies extraterritorialities hypercholesterolemias hypersusceptibilities immunocytochemistries immunoelectrophoreses immunoelectrophoresis incomprehensibilities indistinguishableness institutionalizations interchangeablenesses interconvertibilities internationalizations isopropylcyclohexanes isopropylcyclohexenes lymphoscintigraphists magnetostratigraphers magnetostratigraphics meningoencephalitides meningoencephaloceles microminiaturizations micropalaeontologists mucopolysaccharidosis multidimensionalities neuroendocrinologists nondenominationalisms nonillionsedecillions noventrigintillionths otorhinolaryngologies oversuperstitiousness palaeoanthropologists perhydrophenanthrenes phaeochromocytoblasts photophosphorylations polyhydroxyalkanoates pseudocholinesterases pseudosophistications psychopharmacologists quadringentilliardths quattuordecilliardths quattuorvigintillions quinquagintilliardths quinquatrigintillions quinquavigintilliards salpingoophorectomies septemvigintillionths sesquinquagintillions sigmoidoproctostomies spondyloarthropathies straightforwardnesses tectonostratigraphers tectonostratigraphics tetrahydrocannabinols trigintacentillionths unconstitutionalities undemonstrativenesses unexceptionablenesses unquinquagintilliards zygomaticoauricularis