18 letters
- radiochromatograms32
- rambunctiousnesses31
- rechromatographies33
- rechromatographing36
- reconstructionisms30
- remunerativenesses28
- rhabdomyosarcomata35
- sedimentologically33
- semiconservatively36
- semidomestications29
- semipermeabilities31
- semiprofessionally32
- semiquantitatively39
- sentimentalization34
- simplemindednesses32
- simultaneousnesses26
- somnambulistically37
- spectrofluorimeter32
- spectrofluorometer32
- spectrofluorometry34
- spectrophotometers32
- spectrophotometric35
- sphygmomanometries37
- stoichiometrically33
- submicroscopically41
- superadministrator27
- superconglomerates32
- superminicomputers36
- telecommunications34
- thermoluminescence36
- thermoplasticities30
- thrombophlebitides36
- transcendentalisms29
- transformationally30
- transilluminations27
- transmissibilities26
- transmogrification31
- triboluminescences34
- ultraconservatisms31
- ultramicroscopical36
- uncompromisingness36
- ungrammaticalities32
- uniformitarianisms30
- valetudinarianisms30
- verisimilitudinous30