Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
ampleness is a noun meaning "the property of being more than sufficient; comfortable sufficiency". It carries 2 recorded senses.
the property of being more than sufficient; comfortable sufficiency
“the ampleness of her servings more than satisfied his hunger”
the property of impressive largeness in size
“he admired the ampleness of its proportions”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for ampleness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.