How to Write Latin Phrases in Italics or Roman Type
Latin expressions appear throughout English prose, from legal documents and academic articles to medical notes, newspaper headlines, and everyday conversation. A writer may use ad hoc to describe a purpose-built arrangement, et cetera to shorten a list, or status quo to refer to an existing state of affairs. The phrase may be familiar, but its typography still raises a practical question: should it appear in italics or in ordinary roman type?
There is no single rule that governs every Latin word. Italics often signal that a phrase remains recognizably foreign, while roman type suggests that English has absorbed it. Yet usage depends on the expression, the discipline, the publication’s style guide, and the degree to which readers perceive the wording as part of normal English.
Good typography therefore requires more than memorizing a list. It involves identifying the function of the phrase, checking how established it is in the relevant field, and applying one consistent policy throughout a document. The distinction also reveals how languages change: a Latin phrase can begin as an imported quotation and gradually become an ordinary English term.
What Italics Communicate
Italic type traditionally marks a word or phrase that stands outside the grammatical body of English. In this role, italics tell the reader, “This expression comes from another language.” A phrase such as sine qua non or in vino veritas retains a strongly Latin identity for many English readers, so italics are a sensible choice in general prose.
Italics can also preserve the character of a quotation, motto, technical label, or scholarly term. A historian might write about damnatio memoriae, the Roman practice of condemning someone’s memory, while a legal scholar might discuss amicus curiae, a person or organization offering information to a court. The visual distinction helps readers recognize that the phrase carries specialized cultural or historical meaning.
The choice is not a judgment about whether the Latin is “correct” or prestigious. Italics are a typographic signal, not a decoration. They should clarify the relationship between the expression and the surrounding English rather than make every Latin-derived word appear unusually formal.
When a phrase is italicized, related punctuation usually remains in roman type unless it belongs directly to the italicized material. For example, a sentence may read, “The ruling established a prima facie case.” The period is not part of the Latin phrase. This small distinction matters in carefully edited academic and professional writing.
When Roman Type Is Appropriate
Roman type, sometimes called regular or upright type, is generally appropriate when a Latin expression has become a familiar part of English vocabulary. Common examples include agenda, alias, versus, senior, junior, alibi, bona fide, per se, and vice versa. Many style guides treat these terms as fully naturalized, even though their origins are Latin.
Naturalization is a matter of usage rather than age alone. Agenda began as a Latin plural meaning “things to be done,” but modern English commonly uses it as a singular noun. Most readers no longer experience the word as foreign. Italicizing it in ordinary business writing may therefore look unnecessary or even distracting.
Some expressions occupy a middle ground. Et al., etc., per capita, in vitro, ad hoc, and status quo are widely understood, but different style manuals handle them differently. A scientific journal may use roman type for in vitro, whereas a general publisher may retain italics because the phrase still feels foreign. Both decisions can be defensible when they follow an established editorial policy.
The important principle is consistency. If a writer uses roman type for ad hoc in one chapter, italicizing it in another without a change in meaning creates visual inconsistency. A house style may choose one treatment for all recurring expressions, even when dictionaries and external style guides show variation.
Readers seeking historical background and definitions can consult a Latin sayings reference before deciding whether a phrase is a quotation, a technical term, or a familiar English borrowing. Understanding the original meaning often makes the typographic choice easier.
Why Style Guides Differ
Style guides serve different audiences, so they do not always classify Latin phrases in the same way. A legal manual may prioritize established courtroom usage, a scientific guide may focus on international conventions, and a humanities guide may preserve foreign-language distinctions more carefully. The preferred form in one publication can therefore differ from the form used by another reputable source.
Academic writing often follows a conservative approach. In fields such as classics, history, philosophy, and religious studies, italicizing an unassimilated Latin phrase helps distinguish the original language from the English analysis. A paper might use ex nihilo and mutatis mutandis in italics while leaving “agenda” and “alumni” in roman type.
Scientific and medical writing frequently uses roman type for Latin phrases that function as standardized technical terms. Expressions such as in vivo, in vitro, in situ, and ex vivo may appear upright in journal articles, especially when they describe established experimental conditions. Scientific style also tends to prioritize readability, searchable terminology, and consistency across large bodies of research.
Legal writing has its own conventions. Terms such as habeas corpus, bona fide, pro se, and prima facie may appear in roman type in some court systems and in italics in others. A legal writer should follow the jurisdiction’s court rules or the publication’s editorial guide rather than rely on a general assumption about foreign words.
The safest hierarchy is practical: first follow a required style guide, then follow the publication’s house style, and only then use personal preference. If no authority is specified, choose a clear policy, apply it consistently, and avoid changing treatment simply because a phrase appears several times.
A Practical Typographic Guide
The following comparison provides a useful starting point for general English prose. It reflects common editorial practice, but individual disciplines may adopt different conventions.
| Expression or category | Usual treatment in general prose | Example | Reason |
|---|---|---|---|
| Fully naturalized English words | Roman type | agenda, alibi, alias | Readers usually regard them as ordinary English |
| Familiar borrowed phrases | Often roman type | bona fide, per se, vice versa | They are common and widely understood |
| Clearly foreign or literary sayings | Italics | carpe diem, sine qua non | The Latin identity remains prominent |
| Specialized scholarly terms | Usually italics on first use | damnatio memoriae | Italics signal an unfamiliar technical concept |
| Scientific conditions | Follow the journal style | in vitro, in vivo | Scientific publications often standardize these terms |
| Legal terms | Follow the court or publisher style | habeas corpus, prima facie | Legal conventions vary by jurisdiction |
| Abbreviations | Usually roman type | etc., e.g., i.e. | Common abbreviations function as punctuation-like English forms |
| Latin titles or mottos | Often italics | De rerum natura | The title remains a foreign-language work or phrase |
| Repeated defined terms | Use the chosen form consistently | ex post facto throughout | Consistency helps readers follow the argument |
A first-use policy can solve many borderline cases. Italicize a less familiar expression when it first appears, give its English meaning, and then use roman type later if the phrase becomes a defined technical term. For example: “The practice of damnatio memoriae, or the deliberate erasure of a public figure’s memory, shaped the monument.” A writer may retain italics throughout, or switch after definition if the style guide permits it.
However, switching styles mid-document should be deliberate rather than automatic. Readers do not need a phrase to change appearance merely because it has been explained. In a short article, retaining italics may be clearer. In a long research paper, roman type after first definition may reduce visual clutter. The publication’s expectations should determine the choice.
Latin Phrases in Different Contexts
Context affects how a phrase is perceived. In a formal essay, ad hoc may describe a temporary committee, and the writer may italicize it to emphasize its Latin origin. In a newspaper sentence such as “The mayor created an ad hoc panel,” roman type may be more natural because the phrase is functioning as a familiar adjective.
A motto or quotation deserves separate treatment. If the Latin is presented as the official wording of an institution, it may be italicized as a foreign-language statement or set in quotation marks according to the surrounding design. Translation should normally be provided when the meaning is not obvious to the intended audience. Typography cannot replace explanation.
Book and film titles containing Latin follow the publication’s title rules. A Latin title may be italicized because it is the title of a standalone work, not merely because it is Latin. For example, De rerum natura is italicized as a book title under many English conventions. A short Latin motto inside a sentence may require a different treatment.
Plural and possessive forms also create uncertainty. Common English forms such as alumni, alumna, and syllabus are generally handled according to English grammar. Less familiar phrases should not be forced into an invented Latin plural merely to appear learned. If a phrase is being used as an English noun, a plain English construction can often avoid awkwardness: “several examples of modus operandi” is clearer than imposing a controversial plural.
Capitalization follows meaning and position, not the language’s ancient status. A Latin phrase in the middle of a sentence usually remains lowercase unless it contains a proper name or begins a sentence. The word “Latin” itself is capitalized because it names a language, while a phrase such as in medias res normally is not.
Common Errors To Avoid
One frequent mistake is italicizing every word with a Latin origin. English contains thousands of Latin-derived terms, including words such as information, manual, and animal. Etymology alone does not determine typography. The relevant question is whether the current word or phrase is being used as an English expression or as a recognizable foreign-language item.
Another error is treating italics as a substitute for accuracy. A phrase can be correctly italicized and still be misspelled, mistranslated, or used in the wrong context. Writers should check vowel length only when the chosen convention requires macrons, verify the phrase’s grammar, and distinguish similar expressions such as in loco and in situ.
Overusing Latin can also weaken clear prose. A familiar English equivalent is often preferable when the audience does not need the original phrase. “For this purpose” may communicate more efficiently than ad hoc in a general instruction, while inter alia may be unnecessary when “among other things” is perfectly precise.
- Check the target publication’s style guide before making a final decision.
- Use italics for unfamiliar or deliberately foreign expressions, not every Latin-derived word.
- Keep recurring phrases in the same type style throughout a document.
- Define specialized Latin terminology at first use when readers may not know it.
- Prefer a clear English equivalent when the Latin adds no useful precision or tone.
Building A Consistent House Style
Editors working on a book, website, course, or journal can create a short internal list of common expressions. The list might classify ad hoc, bona fide, et cetera, in situ, per se, and status quo, while noting exceptions for quotations, titles, and discipline-specific usage. Such a reference prevents repeated decisions and keeps multiple contributors aligned.
A style sheet should also record punctuation and abbreviation preferences. Decide whether to use “etc.” or “et cetera,” whether ibid. is permitted, how to handle e.g. and i.e., and whether phrases receive italics after their first definition. These choices may seem minor, but they become visible across a long publication.
Digital writing adds another consideration: accessibility. Italics are conveyed differently by screen readers and may not be perceived by every reader. A phrase should remain understandable without relying solely on visual formatting. Give a translation, explanation, or contextual clue when meaning matters, especially in educational content.
Searchability and consistency matter online as well. A website explaining Latin sayings may use italics for quotations and rare expressions while keeping naturalized English words upright. The decision should be reflected in page templates, editorial reviews, and updates, so readers encounter a stable pattern rather than arbitrary changes.
Typography works best when it supports meaning quietly. Italics can preserve a phrase’s foreign identity, roman type can acknowledge its place in English, and explanation can bridge the gap between the two. Once the writer understands those functions, choosing between the styles becomes a reasoned editorial decision rather than a matter of guesswork.
Apply the same method to your next essay, article, lesson, or professional document: identify the phrase’s role, consult the relevant authority, explain unfamiliar language, and use one consistent treatment. Over time, your command of Latin typography will become part of a broader skill—the ability to make historical language clear and useful for modern readers.