WordReference English-Spanish Dictionary © 2014:

Principal Translations
de casualidad loc preplocución preposicional: Unidad léxica estable formada de dos o más palabras que funciona como preposición ("a favor de", "en torno a"). (por azar)by chance preppreposition: Relates noun or pronoun to another element of sentence--for example, "a picture of John," "She walked from my house to yours."
  by happenstance preppreposition: Relates noun or pronoun to another element of sentence--for example, "a picture of John," "She walked from my house to yours."
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WordReference English-Spanish Dictionary © 2014:

Compound Forms:
da la casualidad de que fr hecha (pues)it just so happens that exprexpression: Prepositional phrase, adverbial phrase, or other phrase or expression--for example, "behind the times," "on your own."
todo eso no es fruto de la casualidad that's not a chance result
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'de casualidad' found in these entries
In the Spanish description:
English:

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