2 syllables:
cession, deshane, deshon, eschen, flesh in, freshen, fresh in, heshen, hessian, hession, leshan, pression, pressione, question, session, sheshan, teschen

3 syllables:
abscession, accession, addression, aggression, agression, assession, bull session, closed session, compression, concession, confession, congression, decession, degression, depression, digression, discession, discretion, egression, espressione, excession, expression, helvetian, impression, incession, ingression, insession, jam session, mancession, midsession, monecian, noetian, obsession, oppression, perpession, possession, precession, profession, progression, rap session, recession, refreshen, regression, repression, s-expression, seccession, secession, sezession, skull session, succession, sucession, suppression, supression, transgression, vanessian

4 syllables:
de-accession, deaccession, decompression, derepression, dispossession, great depression, health profession, indiscretion, intercession, intersession, introcession, introgression, intropression, learned profession, misexpression, misimpression, multisession, non-aggression, non-possession, nonaggression, practice session, prepossession, radieschen, recompression, reimpression, repossession, retrocession, retrogression, self-expression, self-possession, sense impression, special session, subingression, supersession, uncompression, wage concession

5 syllables:
circumincession, facial expression, image compression, kathavasheshan, legal profession, line of succession, manic-depression, manic depression, meta-regression, microaggression, microexpression, overexpression, peripatecian, photo-secession, secret obsession, simple regression, taking possession, transferred possession, without expression

6 syllables:
clinical depression, executive session, harmonic progression, immunosuppression, indirect expression, linear regression, medical profession, multiple regression, myelosuppression, natural depression, neurotic depression, psychotic depression, reactive depression, retarded depression

7 syllables:
agitated depression, arithmetic progression, covid-19 recession, economics profession, exogenous depression, exponential expression, geometric progression, material possession

8 syllables:
chronological succession, ecological succession, idiomatic expression, war of the spanish succession

9 syllables:
war of the austrian succession

2 syllables:
evan, essen, caisson, cresson, heaven, stetson, seven, devon, lesson, lessen, leaven, resin, deafen

3 syllables:
eleven, fluorescein, gum resin, dance lesson, french lesson, golf lesson, phaethon

4 syllables:
object lesson, tree of heaven, seventh heaven, german lesson, hebrew lesson, language lesson, music lesson, tennis lesson, twenty-seven, vault of heaven, vinyl resin

5 syllables:
synthetic resin, epoxy resin, phenolic resin, acrylic resin, melamine resin, delicatessen, amino resin, cannabis resin, history lesson, manna from heaven, natural resin, piano lesson, silicone resin, violin lesson

6 syllables:
polyvinyl resin, thermoplastic resin, thermosetting resin