Letter case

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The upper-case "A" and lower-case "a" are the two case variants of the first letter in the English alphabet.

In orthography and typography, letter case (or just case) is the distinction between the letters that are in larger upper case (also capital letters, capitals, caps, majuscule, or large letters) and smaller lower case (also minuscule or small letters) in certain languages. In the Latin script, upper case letters are A, B, C, etc., whereas lower case includes a, b, c, etc. Here is a comparison of the upper and lower case versions of each letter included in the English alphabet (the exact representation will vary according to the font used):


The lower case is the normal and more common variant, contrasted by the upper case, which is used for special purposes, for example as the first letter of a sentence or a proper noun. Languages have capitalisation rules to determine whether an upper or lower case letter is to be used in a given context, but there can also be stylistic variation.


Divided upper and lower type cases for movable type




Bicameral script[edit]

Williamsburg 18th-century press letters

Most Western languages (particularly those with writing systems based on the Latin, Cyrillic, Greek, Coptic, and Armenian alphabets) use letter cases in their written form as an aid to clarity. Scripts using two separate cases are also called bicameral scripts. Many other writing systems (such as the Georgian, Glagolitic, Arabic, Hebrew, Devanagari, and Hangul alphabets, not to mention Chinese or Kana character sets), make no distinction between capital and lowercase letters – a system called unicameral script or unicase.

If an alphabet has case, all or nearly all letters have both forms. Both forms in each pair are considered variants of the same letter: they have the same name and pronunciation and will be treated identically when sorting in alphabetical order.

In scripts with a case distinction, lower case is generally used for the majority of text; capitals are used for capitalisation, acronyms, and emphasis (in some languages).


Capitalisation is the writing of a word with its first letter in uppercase and the remaining letters in lowercase. Capitalisation rules vary by language and are often quite complex, but in most modern languages that have capitalisation, the first letter of every sentence is capitalised, as are all proper nouns.

Capitalisation in English, in terms of the general orthographic rules independent of context (e.g., title vs heading vs text), is universally standardized for formal writing (informal communication, such as texting, instant messaging, or a handwritten sticky note, may not bother, but that is because its users usually do not expect it to be formal). In English, capital letters are used as the first letter of a sentence, a proper noun, or a proper adjective. There are a few pairs of words of different meanings whose only difference is capitalisation of the first letter. The first-person pronoun "I" and the interjection "O" are also capitalised. Initialisms or acronyms are generally written in all-caps in American English, whereas British English only capitalises the first letter of an acronym (pronounced as a word) – or none if it is regarded as an everyday word.[3] Lower case letters are normally used for all other purposes. There are however situations where further capitalisation may be used to give added emphasis, for example in headings and titles or to pick out certain words (often using small capitals). In some traditional forms of poetry, capitalisation has conventionally been used as a marker to indicate the beginning of a line of verse independent of any grammatical feature.

Other languages vary in their use of capitals. For example, in German the first letter of all nouns is capitalised (this was previously common in English as well), while in Romance and most other European languages the names of days of the week, months of the year, and adjectives of nationality, religion and so on generally begin with a lower case letter.

Exceptional letters[edit]

  • The German letter "ß" primarily exists in lower case and is capitalised as "SS" (but see Capital ß).
  • The Greek letter "Σ" has two different lower case forms: "ς" in word-final position and "σ" elsewhere. In a similar manner, the Latin letter "S" used to have two different lower case forms: "s" in word-final position and "ſ" elsewhere. The latter form, called the long s, fell out of general use before the middle of the 19th century.
  • The Cyrillic letter "Ӏ" usually has only a capital form, which is also used in lower case text.
  • Unlike most Latin-script languages, which link the dotless upper case "I" with the dotted lower case "i", Turkish has both a dotted and dotless I in upper and lower case. Each of the two pairs ("İ/i" and "I/ı") represent a distinctive phoneme.
  • In Dutch, the digraph "ij" is capitalised as a single entity, "IJ".[4]

Related phenomena[edit]

Similar orthographic conventions are used for emphasis or following language-specific rules, including:

Stylistic or specialised usage[edit]

Case styles[edit]

All-caps and title case in New York Times (10 November 1919, on Arthur Eddington's solar eclipse experiment).


  • ALL CAPS: only capital letters are used. Capital letters were sometimes used for typographical emphasis in text made on a typewriter. However, long spans of Latin-alphabet text in all upper-case are harder to read because of the absence of the ascenders and descenders found in lower-case letters, which can aid recognition. With the advent of the Internet, all-caps is more often used for emphasis; however, it is considered poor netiquette by some to type in all capitals, and said to be tantamount to shouting.[5]


Example Rule
The Vitamins Are In My Fresh California Raisins Start case – capitalisation of all words, regardless of the part of speech
The Vitamins Are in My Fresh California Raisins Capitalisation of the first word, and all other words, except for articles, prepositions, and conjunctions
The Vitamins are in my Fresh California Raisins Capitalisation of the first word, and all other words, except for closed-class words
The Vitamins are in my fresh California Raisins Capitalisation of all nouns and the first word
the Vitamins are in my fresh California Raisins Capitalisation only of nouns
The vitamins are in my fresh California raisins Sentence case – capitalisation of only the first word, proper nouns and as dictated by other specific English rules
the vitamins are in my fresh California raisins Mid-sentence case – capitalisation of proper nouns only

Headings and publication titles[edit]

In English-language publications, varying conventions are used for capitalising words in publication titles and headlines, including chapter and section headings. The rules differ substantially between individual house styles.

The convention followed by many British publishers (including scientific publishers, like Nature, magazines, like The Economist and New Scientist, and newspapers, like The Guardian and The Times) is to use sentence-style capitalisation in titles and headlines, where capitalisation follows the same rules that apply for sentences. This convention is usually called sentence case. It is also widely used in the United States, especially in newspaper publishing, bibliographic references and library catalogues. Examples of global publishers whose English-language house styles prescribe sentence-case titles and headings include the International Organization for Standardization.

Among U.S. book publishers, it is a common typographic practice to capitalise significant words in titles and headings. This is an old form of emphasis, similar to the more modern practice of using a larger or boldface font for titles. This family of typographic conventions is usually called title case. The rules for which words to capitalise are not based on any grammatically inherent correct/incorrect distinction and are not universally standardized; they are arbitrary and differ between style guides, although in most styles they tend to follow a few strong conventions, as follows:

  • Most styles capitalise all words except for closed-class words (certain parts of speech, namely, articles, prepositions, and conjunctions); but the first word (always) and last word (in many styles) are also capped, regardless of part of speech. Many styles capitalise longer prepositions such as "between" or "throughout", but not shorter ones such as "for" or "with".[6] Among such styles, "four or more letters (≥4)" or "more than four letters (>4)" are the typical (although arbitrary and conflicting) threshold rules.

One British style guide mentions a form of title case: R. M. Ritter's Oxford Manual of Style (2002) suggests capitalising "the first word and all nouns, pronouns, adjectives, verbs and adverbs, but generally not articles, conjunctions and short prepositions".[7]



Special case styles[edit]


  • CamelCase: first letter of each word is capitalised, spaces and punctuation removed. If the very first letter is capitalized, as in "CamelCase" (or "PowerPoint"), the term upper camel case may be used; this is also known as Pascal case or bumpy case. Lower camel case describes a variation, as in "camelCase" (or "iPod" or "eBay"), in which the very first letter is in lower case. CamelCase derives from computer programming, but it has also become rather common in brand names of information technology products.
  • Train-Case or spinal-case (depending on whether or not the first letter of each word is in upper case, respectively): similar to snake case, but spaces are replaced by hyphens, instead of underscores.

Metric system[edit]

In the International System of Units (SI), a letter usually has a different meaning in upper and lower cases when used as a unit symbol. A unit symbol is normally written in lower case, but if the name of the unit is derived from a proper noun, the first letter of the symbol is written in upper case (nevertheless, the name of the unit, if spelled out, is always considered a common noun and written accordingly):[9]




  • 1 mS, a small measure of electric conductance.
  • 1 MS, a large measure of electric conductance.
  • 1 Mm, a large measure of length.

Case folding[edit]


Methods in word processing[edit]


Methods in programming[edit]


 UpperA$ = UCASE$("a")
 LowerA$ = LCASE$("A")


 char upperA = toupper('a');
 char lowerA = tolower('A');



This only works because the letters of upper and lower cases are spaced out equally. In ASCII they are consecutive, whereas with EBCDIC they are not; nonetheless the upper case letters are arranged in the same pattern and with the same gaps as are the lower case letters, so the technique still works.


Unicode case folding and script identification[edit]




Latin majuscule inscription on the Arch of Titus (82 AD)








Type cases[edit]

Combined case with capital letters above small letters
Late 19th-century mixed cases






See also[edit]


  3. ^ "The Guardian and Observer Style Guide". Retrieved 5 March 2014. 
  5. ^ RFC 1855 "Netiquette Guidelines"
  8. ^ "Ruby Style Guide". Retrieved 11 November 2013. 

External links[edit]