Manual: Latin abbreviations and acronyms

Disclaimer Most of the abbreviations listed in this article are understood by speakers of different languages. However, all 23 abbreviations are only adopted and exist as a fixed standard in English; therefore, we recommend using them with caution when dealing with a text written in a different language.

AD (anno Domini, ‘in the year of the Lord’) is an acronym indicating that an event in question occurred after the birthdate of Jesus Christ. In most cases, AD is placed after the date. However, if the sentence does not contain a year but a century spelled out in words, any abbreviation should sit after it. For example, ‘the third century AD’.

The Oxford Dictionary and Webster’s Dictionary recommend writing AD without periods. The variant with periods is also used, but it is now considered outdated. AD is often set in small caps.

Monachi Sancti Albani, Chronica majora, Matthæi Parisiensis, 1240–1247. 1872 reprint. Image: University of Toronto

Omit periods unless the abbreviation is geographical (e.g., B.C. for British Columbia) or refers to a person.
Canadian Press Stylebook

a.m. and p.m.

There are several ways to write the acronyms a.m. (ante meridiem, ‘before midday’) and p.m. (post meridiem, ‘after midday’), and technically, any of them can be used in modern typography.

Although until 2003, the Chicago Manual of Style maintained that these abbreviations should be set in small caps, it now recommends using periods and lowercase letters as the proper option. The same spelling is recommended by the APA Style. Webster’s Dictionary, however, considers best practice to omit periods (am, pm).

Proceedings of the Old Bailey Criminal Court, 1880. Image: Old Bailey Online

ca. and c.

The Latin word circa (‘approximately’) is abbreviated as c. or ca. and often used when the date of an event is unknown. According to Webster’s Dictionary and the APA guidelines, ca. is the preferred abbreviation.

Сa. should be spaced from the year with a thin space. If we are to indicate an approximate period, the abbreviation should be used before each date that is not known exactly. If the years in the text are given in brackets, the APA guidelines recommend enclosing approximate dates (with the ca. abbreviation) within square brackets, and precise dates within parentheses.

CV

CV stands for curriculum vitae, which translates to ‘course of life’. In the modern world, the term is used to refer to a document that briefly describes a person’s educational background, work experience, and professional skills. This acronym is always spelled with uppercase letters and without periods.

et al.

Et al. — Latin et alii, meaning ‘and others’ — is used when citing or mentioning a source with multiple authors.

The APA Style, which is mainly used in the human sciences, suggests using et al. if a source has three or more authors, whereas the Chicago Manual of Style, used by publishers, argues that it should only be used if there are more than four authors. The abbreviation is placed after the name of the first author.

etc.

Etc. is an abbreviated Latin phrase et cetera, which means ‘and so on’ or ‘and others’. It is used to indicate that there are more items in a list than those listed.

The items listed must be in the same category. For example, “Please buy our weekly vegetables: broccoli, squash, peppers, etc.” is correct, but “Please buy items we need for the house: broccoli, light bulbs, etc.” is not. Shundalyn Allen Grammarly Education

It is recommended to write out et cetera in academic writing. However, it is fine to use the abbreviated version for texting or letters, as well as in documents such as technical specifications or business quotes.

If the etc. sits at the end of a list, it should be preceded by a comma.

An ampersand — a ligature of the letters e and t — used instead of the first two letters in etc. Experiments and considerations touching colours. Robert Boyle, 1670. Image: Wellcome Library

e.g.

E.g. is an abbreviated Latin phrase _exempli gratia_ — ‘for the sake of example’. It must be set off by commas. It is not recommended to place etc. at the end of a list that starts with e.g.

The acronym is written in lowercase letters, with periods after each letter and no spaces between them.

ff. и et seq.

ff. is an abbreviated Latin word foliis, which could be translated as ‘leaves’ or ‘sheets’. It is used in academic writing when the author is referring not to a single chapter or page but to several consecutive chapters or pages. In this case, ff. is placed after the number of the first chapter or page. Until 2009, the Chicago Manual of Style recommended separating the page number from the abbreviation with a thin space; however, the most recent version of the guidelines suggests discarding the space altogether.

If you are referring to two consecutive chapters or pages, it is not recommended to use one f. (folio, which is Latin for ‘leaf’). In this case, one should indicate both chapter or page numbers.

Et seq. is an abbreviated Latin phrase et sequentes, meaning ‘and those that follow’ or ‘and the following’. This abbreviation is used to convey the same message as the abbreviation ff. but is less common.

Et seq. and ff. may be utilised in the text of the paper, but not in its bibliography.

The practice of typography, Theodore Low De Vinne, 1904. Image: University of California Libraries

i.e.

I.e. is an abbreviation of the Latin phrase id est, meaning ‘that is’ or ‘in other words’. It is used to clarify or explain what was said before.

This acronym is written in lowercase letters, with periods after each letter and no space between them. It is not advisable to use e.g. and i.e. in one sentence

ibid.

An abbreviation for the Latin word ibidem (‘in the same place’), ibid. is used in academic writing to avoid repeating the title of a source that has already been mentioned. For example, the author first references page 22 of the book and then cites page 105, the first reference would be R. Bringhurst, The Elements of Typographic Style (Hartley and Marks, 2002), 22, whereas the second one — ibid., 105.

Chicago discourages the use of ibid. To avoid repetition, the title of a work just cited may be omitted.
Chicago Manual of Style

In re и re

In re, which means ‘in the matter of’, is used in legal contexts, for example, to indicate the matter or subject of a case or a judicial proceeding. One should space in re from the subject of the dispute (or the name of a child, if it is about contesting child custody) and not use any punctuation marks.

A shortened form of in re, re, is sometimes used in email, in the subject line of a message — it is then capitalised and followed by a colon.

The Oxford Dictionary provides several examples of re used in colloquial English to mean ‘regarding’, although Fowler’s dictionary discourages such usage.

NB or n.b.

Nota bene is Latin for ‘note well’, used in English as ‘to pay attention to’. The Chicago Manual of Style recommends spelling this acronym with uppercase letters and without periods (NB), or with lowercase letters and with periods (n.b.). The Oxford Dictionary prioritises the first variant, while St. Martin’s Handbook opts for uppercase letters with periods (N.B.)

The Tutor’s Guide: Being a Complete System of Arithmetic, Charles Vyse, 1746. Image: Google Books

Today, the most common spelling is NB, with the word ‘Note’ often used instead of this Latin acronym.

According to the Cambridge Dictionary, NB is also used as an abbreviation for the word ‘non-binary’, in which case it is pronounced as [enby].

No.

An abbreviated Latin word numero, No. is used before the number — for example, of a contract, patent, or building. In some regions, such as Australia and French-speaking Canada, it is common practice to use the symbol № in such contexts, while in the UK, the abbreviation No. is the most popular choice for these purposes. In the US, No. is utilised in formal contexts, while in informal contexts, the number is most often preceded by the symbol #.

P.S. or PS

P.S. (or PS) is an abbreviation for the Latin term post scriptum, which translates to ‘written after’. The acronym may be written with periods as well as without them. The P.S. form is more commonly used in British English (and recommended by the Cambridge Dictionary), with the PS variant being more prevalent in American English (this spelling is considered correct by the Chicago Manual of Style). The version without periods is followed by a colon, while the version with periods is normally used without any extra punctuation marks.

Sometimes, there may be more than one postscript in a text or letter, in which case the second one is to be referred to as a post-postscript.

From a letter Joseph Collet sent to the Reverend Nathaniel Hodges, 1717. Image: Digital Library of India

Since modern technology makes it so easy to revise and add to texts, in most cases, it’s better to just go back and insert the additional material at an appropriate point in the main body of the writing. A post-postscript makes you look not only ignorant, but lazy. Prof. Paul Brians Common errors in English usagen

Since ps (in lowercase letters and without periods) is an abbreviation for PostScript file format, it is better to avoid using it to refer to a postscript.

Ph.D. or PhD

The abbreviation Ph.D., or PhD, stands for the Latin term philosophiae doctor (‘doctor of philosophy’) and now means the next academic degree after a master’s degree. Although the degree title contains the word ‘philosophy’, a person can obtain a Ph.D. (or PhD) in any field. Webster’s Dictionary and APA Style advise writing the abbreviation with periods, while the Chicago Manual of Style argues that one needs to omit them.

Ph.D. (or PhD) is written after the full name, with a comma needed between the name and the degree.

q.v.

The Latin phrase quod vide (‘see which’) is a term used in academic writing as ‘see’ or ‘refer to’. Q.v. is used to indicate that further information about the mentioned topic or event can be found in a different chapter or another section of the same document. The abbreviation is always enclosed in square brackets and not accompanied by a specific chapter where further information can be found, assuming the reader can locate it within the paper by themselves.

Modern guidelines on formatting academic papers advise against using this abbreviation, considering it inconvenient and outdated.

Dictionary of national biography, Sir Stephen Leslie, 1895–1900. Image: University of Toronto

SOS

SOS stands for the Latin phrase si opus sit, which translates as ‘if necessary’, and is used in medical prescriptions, such as for painkillers, indicating that the drug should be taken only when the need arises.

A Morse code distress signal, SOS, does not have anything to do with the Latin phrase si opus est.

vs, vs. amd v.

An abbreviation for the Latin word versus — ‘facing’, ‘towards’ — is used to indicate opposition, such as between two sports teams, and comparison. It is common practice to omit the period at the end of it in British English, while in American English, it is typically written with a period.

Versus can also be abbreviated as v., with this variant only used in legal contexts.

In a number of areas, the English language is possessed of an embarrassment of riches, with multiple synonyms or abbreviations for a word. One such case is versus, which is often written in a shortened form.
Merriam-Webster Dictionary