Use italics to differentiate or to give greater prominence to words and phrases. Italics are signified by underlining in handwritten or typewritten manuscripts.
1. Foreign Words, Phrases, and Abbreviations
Italicize foreign words used in an English context, except words that have become part of our language.
Familiar words and phrases in a foreign language should be set in regular type.
2. Titles of Publications and Related Works
Italicize titles of books, journals, periodicals, newspapers, motion pictures, plays, and other works published separately. (For more information, see section on References.)
3. Names of Vessels, Aircraft, and Spacecraft
Italicize the names of aircraft, vessels, and spacecraft. Missile and rocket names are not italicized. Do not italicize abbreviations such as USS or HMS preceding vessel names.
NOTE: Ship hull numbers should not be hyphenated in NRaD publications; simply leave one space between the type designator and the ship number. Also, it is not necessary to use the article the before the name of a ship unless the ship's name is an adjective modifying a following noun.
Use initial caps, but don't italicize designations of models, names of trains, and names of space programs.
4. Scientific Names
Italicize scientific names of genera, subgenera, species, and subspecies.
Use regular type for the names of groups of higher rank than genera (phyla, classes, orders, families, and tribes).
Print other designations following generic, specific, or subspecific names in regular type.
In mathematical equations, use italics for all letter symbols (caps, lowercase, superscripts, and subscripts). Use regular type for all numbers.
Print chemical symbols, units of measurement, and abbreviations such as log, max, exp, tan, cos, lim, etc., in regular type.