Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
db is a noun meaning "a transuranic element". It carries 2 recorded senses.
a transuranic element
a logarithmic unit of sound intensity; 10 times the logarithm of the ratio of the sound intensity to some reference intensity
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 db come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.