LawProse Lesson #215: How do you decide which Latin phrases to italicize?

How do you decide which Latin phrases to italicize and which ones to keep in roman type? The answer depends on how thoroughly naturalized the word, abbreviation, or phrase has become in English. If the term has become so commonplace in English that it is said to be “anglicized,” it stays in roman type; if it’s persistently considered a foreignism, it should be in italics. If that sounds like a fuzzy “rule,” you’re right. Consider that in the best style, the abbreviations “e.g.” (exempli gratia) and “i.e.” (id est) are set in roman even though the full terms are italicized. Here are a few more examples: Italicized a vinculo matrimonii caveat emptor de minimis duces tecum ejusdem generis in loco parentis in pari materia inter alia non compos mentis sensu stricto Not italicized certiorari de facto en banc habeas corpus mens rea nunc pro tunc prima facie res judicata stare decisis sua sponte With no bright-line rule for determining when a foreignism becomes anglicized and should no longer be italicized, the best practice is to check the current edition of a reliable dictionary or usage guide. The surest guide for legal terms is Black’s Law Dictionary (10th ed. 2014). Follow the style of the entry’s headword. One last note: remember that a word or phrase—anglicized or not—is always italicized when it is being used as a term rather than for its meaning. So, for example, even though habeas corpus is thoroughly anglicized and therefore set in roman type, it’s properly italicized in this sentence about the term itself. Further reading: The Redbook: A Manual on Legal Style § 3.3, at 80–81 (3d ed. 2013). Garner’s Dictionary of Legal Usage 488 (3d ed. 2011). Black’s Law Dictionary xxxiv (10th ed. 2014). The Chicago Manual of Style §§ 7.49–7.53, at 364–65 (10th ed. 2010). Thanks to Adam M. Hapner for his contributions to this lesson.