say it: ak-suh-DEN-tuhl
accidental is an adjective and noun meaning "happening by chance or unexpectedly or unintentionally". It carries 3 recorded senses.
happening by chance or unexpectedly or unintentionally
“with an inadvertent gesture she swept the vase off the table”
“accidental poisoning”
“an accidental shooting”
not of prime or central importance
“nonessential to the integral meanings of poetry”
“the character's motives remain accidental to the plot”
a musical notation that makes a note sharp or flat or natural although that is not part of the key signature
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 accidental come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.