A Note on Latin Phrases

There's a tendency among some writers to think that sprinkling a little Latin - or worse, Greek - in their writing makes them look like a learned scholar.

It doesn't.

Instead, it indicates either a lack of confidence (hence the need to bolster the text with Latin to prove your erudition to yourself) or gross over-confidence (hence the need to bolster the text with Latin to prove your erudition to others).  Either way, Latin is not the right tool to prove yourself.

Reasoned argument, written in clear, concise English will always win out against stylistic flourishings that do more to highlight your self-esteem issues than your argument.  Writing is a demonstration of the clarity of your thinking; adding phrases from dead languages merely muddies that clarity in unflattering ways.

That being the case, there are of course exceptions where Latin expresses a concept far more concisely or commonly than the equivalent English.  If these expressions are in regular use, you may use them.  Otherwise you may not.  Acceptable Latin phrases in general communication are:

• ad infinitum (if for no other reason than the equivalent "to infinity" will now inevitably be suffixed in the reader's mind by "and beyond!", which is probably not what you intended your writing to inspire)
• ad nauseam
• annus horribilis (but only ever for a British audience, as it is famous in these isles but not necessarily elsewhere)
• a.d., a.m., b.c., p.m. (but never expanded)
• bona fide (but bona fides should be left for small time American hoodlums)
• carpe diem
• caveat emptor
• deus ex machina
• emeritus
• et tu, Brute?
• etc (but only rarely et cetera for emphasis)
• e.g. (but never exempli gratia)
• in extremis
• in flagrante delicto (but only when discussing the nocturnal activities of those who should know better)
• in loco parentis
• in memoriam (but only in formal writing such as an engraving or death notice)
• in situ
• i.e. (but never id est)
• lorem ipsum (although this is almost a proper noun nowadays, and yes, it is Latin despite the widespread belief that it's gibberish)
• magnum opus (but only where what you are referring to is truly such)
• momento mori
• modus operandi (M.O. is also acceptable)
• non sequitar
• N.B. (but never nota bene)
• per se
• persona non grata
• post coital
• P.S. (but never post scriptum)
• quid pro quo
• Q.E.D. (quod erat demonstrandum should not be used unless making a specific point in an academic or scholarly article)
• sic
• sine qua non (but only if you must, and only if you wish to risk pretension)
• terra firma
• vice versa

These may be used in general writing; in technical writing you may only ever use a Latin phrase where not only is that phrase lacking an English equivalent, but also where the phrase is common enough that it is considered to be vernacular.  156 A.D is a good example where the equivalent - "in the year of our Lord 156" - is so anachronistic as to be less understandable than the Latin.  The only time that Latin is otherwise acceptable is when your work is for the Catholic Church and only for the Catholic Church, in which case the more Latin you use the cheaper your translation costs will be. 

If there is an equivalent English phrase that is just as concise, use that.  Inter alia means "amongst other things" or "in amongst".  Both of these are as clear as inter alia and are preferred.  Similarly, exempli gratia can be replaced with "for example", whereas e.g. has the advantage of both concision and common usage. Sui generis translates as "in a class of its own" or "stands apart on merit" and either could be used instead. Tabula rasa can be replaced with "blank slate" unless actually discussing Enlightenment philosophy.

Re is a curious case where thanks to email parlance it has come to be seen simply as an abbreviation of "regarding".  As such its use in the formal sense is almost entirely unknown and therefore should be avoided in any context that is not purely communicative. Similarly, semper fi(delis) has been used so much in TV and films (thank you, NCIS) that it should be considered as reserved for United States Marine Corp personnel only.

In technical fields you can use as many Latin phrases as are proper  - cogito ergo sum, habeas corpus, in utero, primus inter pares, vox populi, etc - but again only where an equivalent English phrase does not exist, or where it does exist but does not carry the same weight of bundled meaning (the cogito being an exemplar of this). Do not use words from within these phrases out of context; there is no need to use ergo when "therefore" will suffice.

There are also many words which are so ingrained in our language that most people wouldn't take them as Latin words - agenda, circa, post mortem, versus. These may be used freely, as may titles of literary works such as Dulce et decorum est. Excelsior! may also be used, but only ironically. Proper nouns, such as Opus Dei should be treated as any other proper noun.


Any other Latin phrase (sic transit gloria mundi, vini, vidi, vici, etc, etc) should be avoided on the grounds that the majority won't understand it, and the English equivalent is perfectly acceptable.  And again, for clarity: No Latin phrases in technical documentation, except a.d., a.m., b.c. and p.m.!