18 letters
- polyesterification31
- polyribonucleotide34
- postpsychoanalytic38
- predestinarianisms27
- proletarianization33
- pronounceabilities31
- propagandistically35
- provincializations40
- psychoanalytically39
- quantificationally40
- quantitativenesses34
- quasiperiodicities35
- questionablenesses34
- radiosensitivities24
- rambunctiousnesses31
- reconstructionisms30
- reconstructionists27
- recrystallizations35
- redistributionists24
- rehospitalizations34
- reinstitutionalize31
- remunerativenesses28
- renationalizations31
- reprehensibilities28
- representationally27
- representativeness27
- representativities26
- revascularizations37
- satisfactorinesses25
- semiconservatively36
- semidomestications29
- semipermeabilities31
- semiquantitatively39
- sentimentalization34
- somnambulistically37
- stereoregularities22
- structuralizations34
- subcategorizations37
- subclassifications33
- substitutabilities27
- supercivilizations40
- supersensitivities27
- supersophisticated31
- supranationalities25
- telecommunications34
- territorialization29
- theatricalizations34
- thermoplasticities30
- thrombophlebitides36
- transformationally30
- transilluminations27
- transistorizations29
- transmissibilities26
- transmogrification31
- transportabilities26
- transubstantiating27
- transubstantiation25
- triboelectricities28
- ultraconservatisms31
- ultraconservatives32
- ultranationalistic26
- ultrarevolutionary29
- ultrasophisticated29
- unaccountabilities32
- unattractivenesses28
- unconstitutionally30
- unenthusiastically31
- ungrammaticalities32
- unpredictabilities31
- unsatisfactoriness27
- unsubstantialities26