MIXEDCase

Mixed case refers to text that contains both uppercase and lowercase letters. The term contrasts with all-lowercase or all-uppercase text and is a natural outcome of alphabetical writing in many languages. In ordinary prose, capitalization rules (such as sentence case or title case) guide mixed-case usage, though the appearance of mixed case can vary by style guide, language, and purpose.

In typography and writing systems, mixed case is the standard for most languages that use the Latin alphabet. Uppercase and lowercase forms originate from historical movable-type practices, but today they primarily serve linguistic and typographic functions—indicating sentence boundaries, proper nouns, emphasis, or the start of new elements within a text. Some contexts favor consistent capitalization patterns (for example, sentence case in body text or title case in headings), while others allow more flexible mixed-case usage for branding or stylistic effect.

In computing and software development, mixed-case naming conventions are common for identifiers. CamelCase and PascalCase are two prominent variants. In camelCase (lowerCamelCase), the first letter is lowercase and each subsequent word begins with an uppercase letter, as in myVariableName. In PascalCase (UpperCamelCase), every word starts with a capital letter, as in MyVariableName. These styles improve readability in languages that use spaces or punctuation to separate words within identifiers.

Other casing styles such as snake_case (lowercase words separated by underscores) and kebab-case (lowercase words separated by hyphens) are also used, depending on language norms and project conventions. The choice of mixed-case or alternative casing affects readability, maintainability, and accessibility, including how screen readers interpret acronyms and capitalizations.