accident vs occasion

accident

noun
  • Chance; random chance. 

  • Any property, fact, or relation that is the result of chance or is nonessential or nonsubstantive. 

  • A person born from an unintended pregnancy. 

  • A collision or crash of a vehicle, aircraft, or other form of transportation that causes damage to the transportation involved; and sometimes injury or death to the transportation's occupants or bystanders in close proximity. (but see Usage notes) 

  • A property attached to a word, but not essential to it, such as gender, number, or case. 

  • An instance of incontinence. 

  • An unexpected event with negative consequences occurring without the intention of the one suffering the consequences, and (in the strict sense) not directly caused by humans. 

  • Urine or feces excreted due to incontinence. 

  • An irregular surface feature with no apparent cause. 

  • A sudden discontinuity of ground such as fault of great thickness, bed or lentil of unstable ground. 

  • A point or mark which may be retained or omitted in a coat of arms. 

  • An unintended pregnancy. 

  • Any chance event. 

  • casus; such unforeseen, extraordinary, extraneous interference as is out of the range of ordinary calculation. 

adj
  • Designating any form of transportation involved in an accident. 

occasion

noun
  • A favorable opportunity; a convenient or timely chance. 

  • Need; requirement, necessity. 

  • The time when something happens. 

  • Something which causes something else; a cause. 

  • A reason or excuse; a motive; a persuasion. 

  • A special event or function. 

  • A particular happening; an instance or time when something occurred. 

  • An occurrence or state of affairs which causes some event or reaction; a motive or reason. 

verb
  • To cause; to produce; to induce 

How often have the words accident and occasion occurred in a corpus of books? (source: Google Ngram Viewer )