The practice of marking all word boundaries in long identifiers (such as ThisIsASampleVariable) (including the first letter of the identifier) with uppercase. Constrasts with camelCasing, in which the first character of the identifier is left in lowercase (thisIsASampleVariable), and with the traditional C style of short all-lower-case names with internal word breaks marked by an underscore (sample_var).

Where these terms are used, they usually go with advice to use PascalCasing for public interfaces and camelCasing for private ones. They may have originated at Microsoft, but are in more general use in ECMA standards, among Java programmers, and elsewhere.