About
The case of a letter refers to its representation.
The most known cases are:
- upper case (ie UPPERCASE, LOWERCASE)
- and lower case (ie lowercase, uppercase)
but there is more:
- Camel Case: UserCount used in java code for instance
- Snake Case: user_count used in properties for instance
- SQL Case: USER_COUNT used in SQL (known also as SCREAMING_SNAKE_CASE or UPPER_SNAKE_CASE)
- Hyphen Case: user-count also known as kebab-case, lisp-case, etc.
Historically
They refer to the physical cases where printers kept their letters
Where you can see a physical representation of letter frequency.