Uses
Small caps are often used for sections of text that is all uppercase; this makes the run of capital letters seem less jarring to the reader. For example, the style of many American publications, including the Atlantic Monthly and USA Today, is to use small caps for acronyms and initialisms longer than three letters; thus: "U.S." in normal caps, but "nato" in small caps. The initialisms ad, bc, am, and pm are often smallcapped as well.
In printed plays and stage directions small caps are usually used for the names of characters preceding their lines.
French and some British publications use small caps to indicate the surname by which someone with a long formal name is to be designated in the rest of a written work. An elementary example is Don Quixote de La Mancha. Similarly, they are used for those languages in which the surname comes first, such as the romanization Mao Zedong.
In many versions of the Old Testament of the Bible the word "LORD" is set in small-caps. Typically, an ordinary "Lord" corresponds to the use of the word Adonai in the original Hebrew, but the small caps "LORD" corresponds to the use of Yahweh in the original; in some versions the compound "Lord GOD" represents the Hebrew compound Adonai Yahweh.
In zoological and botanical nomenclature it is common use to print names of the family group in small caps.
Linguists use small caps to analyze the morphology and tag the parts of speech in a sentence; e.g.,
She loves you, yeah yeah yeah
3.sg.subj 3.sg.pres.ind. 2.obj. interj.
The Bluebook prescribes small caps for some titles in United States legal citations.
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