Editing Letter case (section)

{{short description|Uppercase or lowercase}}
{{redirect-multi|3|Lowercase|Uppercase|Capital Letters|the musical style|Lowercase (music)|the magazine|Uppercase (magazine)|the song|Capital Letters (song)}}
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[[File:A (capital and small).svg|thumb|159px|The lower-case "a" and upper-case "A" are the two case variants of the first letter in the [[English alphabet]].]]
'''Letter case''' is the distinction between the letters that are in larger '''uppercase''' or '''capitals''' (more formally ''[[#Majuscule|majuscule]]'') and smaller '''lowercase''' (more formally ''[[#Minuscule|minuscule]]'') in the written representation of certain languages. The [[writing system]]s that distinguish between the upper- and lowercase have two parallel sets of letters: each in the majuscule set has a counterpart in the minuscule set. Some counterpart letters have the same shape, and differ only in size (e.g. {{angbr|C, c}} {{angbr|S, s}} {{angbr|O, o}} ), but for others the shapes are different (e.g., {{angbr|A, a}} {{angbr|G, g}} {{angbr|F, f}}). The two case variants are alternative representations of the same letter: they have the same name and [[pronunciation]] and are typically treated identically when sorting in [[alphabetical order]].

Letter case is generally applied in a mixed-case fashion, with both upper and lowercase letters appearing in a given piece of text for legibility. The choice of case is often denoted by the [[grammar]] of a language or by the conventions of a particular discipline. In [[orthography]], the uppercase is reserved for special purposes, such as the first letter of a [[Sentence (linguistics)|sentence]] or of a [[proper noun]] (called capitalisation, or capitalised words), which makes lowercase more common in regular text.

In some contexts, it is conventional to use one case only. For example, [[Engineering drawing|engineering design drawings]] are typically labelled entirely in uppercase letters, which are easier to distinguish individually than the lowercase when space restrictions require very small lettering. In [[mathematics]], on the other hand, uppercase and lowercase letters denote generally different [[mathematical object]]s, which may be related when the two cases of the same letter are used; for example, {{mvar|x}} may denote an element of a [[set (mathematics)|set]] {{math|''X''}}.