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Starting Things With Ab Initio
We'll tell you right from the beginning where ab initio comes from. This adverb was adopted at the beginning of the 17th century directly from Latin, where it translates as "from the beginning." (Initio is a form of the noun initium, meaning "beginning," which gave rise to such English words as initial, initiate, and initiative.) Ab initio most frequently appears in legal contexts, but it is not surprising to find it used outside of the courtroom. The phrase is also used as an adjective meaning "starting from or based on first principles" (as in "predicted from ab initio calculations").
Examples of ab initio in a Sentence
Virginia La Torre Jeker, Forbes.com, 12 July 2025
And at the same time, powerful computer simulations, known as ab initio models, are helping predict how iron and nickel behave under conditions no lab can replicate.
—Jake Parks, Discover Magazine, 9 July 2025
Even less so is the 1917 Liberty Bond Act, which has long since been superseded by a new Congressional budget process that has determined its own ‘ceiling’ by budgeting itself since 1974, and was of doubtful 14th Amendment conformity, at least as now interpreted by Republicans, ab initio in 1917.
—Robert Hockett, Forbes, 7 May 2023
So, the ability to scale and diversify must be built ab initio into any decision to build a syn-bio stack.
—Nicolas Goeldel, Fortune, 3 Mar. 2023
But some countries do not allow either of these procedures, and instead require that the whole lawsuit be tried ab initio as if the foreign proceedings never occurred.
—Jay Adkisson, Forbes, 23 Jan. 2023
What McConnell needed to do, for his argument to establish its conclusions, was to provide independent grounds of some kind for ruling out Interpretation B ab initio.
—Jason Lee Steorts, National Review, 15 May 2021
Moreover, the Executive Order exceeds the President’s authority and is therefore ultra vires and void ab initio.
—Eriq Gardner, Billboard, 4 Sep. 2020
Cite this Entry
“Ab initio.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ab%20initio. Accessed 18 Jul. 2025.
Copy CitationLegal Definition
ab initio
adverb
Latin
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