Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
perpendicularly is an adverb meaning "straight up or down without a break". It carries 2 recorded senses.
straight up or down without a break
in a perpendicular manner
“this red line runs perpendicularly to the green line”
Definitions, synonyms and semantic relations for perpendicularly come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.