ab initio

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Alternative forms[edit]

ab init


From Latin ab (from) + initiō, ablative singular of initium (beginning).


  • (US) IPA(key): /ˌæb ɪˈnɪʃ.i.oʊ/, /ˌæb əˈnɪt.i.oʊ/, /ˌɑb əˈnɪt.i.oʊ/


ab initio

  1. (law) From the time when a legal document comes into force. [Early 17th century.][1]
  2. (sciences) Calculated from first principles, i.e. from basic laws without any further additional assumptions.
    • 1983, Monty Python, The meaning of life, at about 1h 15':
      [] this soul does not exist ab initio, as orthodox Christianity teaches; it has to be brought into existence by a process of guided self-observation. However, this is rarely achieved, owing to man's unique ability to be distracted from spiritual matters by everyday trivia.
  3. (of an academic course) Taken with no prior qualifications.



  1. ^ “ab initio”, in Lesley Brown, editor-in-chief; William R. Trumble and Angus Stevenson, editors, The Shorter Oxford English Dictionary on Historical Principles, 5th edition, Oxford; New York, N.Y.: Oxford University Press, 2002, →ISBN, page 4.