Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
plenarily is an adverb meaning "in a plenary manner". It carries one recorded sense.
in a plenary manner
“an empire destined to enter the Commonwealth plenarily”
Definitions, synonyms and semantic relations for plenarily come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.