The Latin preposition de takes an ablative object and has several different translations including 'about', 'of', 'down from' and 'from'. The preposition a/ab also has multiple meanings including 'after', 'by' and 'from'.

Both words can mean 'from'. When the meaning of the word is 'from', is there a difference in usage or meaning and is it preferable to use one over the other?

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    Welcome to the site! Interesting question; I want to see a thorough answer to this one.
    – Joonas Ilmavirta
    Commented Sep 1, 2016 at 11:49
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    Random hypothesis (in case it is worth as a lead for anyone's research): it might have to do with them being applicable to different categories of places, like in Italian in vs a, or (arguably) in Englis in, on, at.
    – Rafael
    Commented Sep 1, 2016 at 16:06
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    @Rafael Interesting... I don't know any Italian - what's the difference between in and a?
    – LJD200
    Commented Sep 3, 2016 at 18:24
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    @LJD200 Not an expert, but you use in for countries and rooms, while a for (specific) cities and buildings. (natural question: what happens with city-states?---I don't know)
    – Rafael
    Commented Sep 4, 2016 at 20:13
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    @fdb It doesn't have to come from the same word - it just illustrates that the Latin words could be applicable to different categories of places like words in some other languages.
    – LJD200
    Commented Sep 5, 2016 at 14:23

2 Answers 2


Like all good questions, this one has no simple answer. The big dictionaries devote many columns to it. Kennedy 286 gives a crisp & useful summary. A couple of firm examples:

  1. Travelling from a place... is ab.

  2. I am of or from the family X... is de.

Nearly always, ab is elided to a before a consonant. See the Oxford Latin Dictionary for exceptions.


A place-holder, until someone writes the perfect answer. Rule of thumb rules:

Avoid an elision or a hiatus by choosing 'ab,' 'abs', in preference to 'a' or 'de.'

ab urbe.

Where 'from' can be replaced by 'down from', pick 'de'

de montibus cucurrit. de turris autem versus concino.

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