Letter Casing Definitions

Formatting	Name(s)
twowords	flat case
TWOWORDS	upper flat case
twoWords	(lower) camelCase, dromedaryCase
TwoWords	PascalCase,Upper Camel Case,StudlyCase
two_words	snake_case, pothole_case
TWO_WORDS	SCREAMING_SNAKE_CASE, MACRO_CASE, CONSTANT_CASE
two_Words	camel_Snake_Case
Two_Words	Pascal_Snake_Case
two-words	kebab-case, dash-case, lisp-case
two|words	doner|case
TWO-WORDS	TRAIN-CASE, COBOL-CASE, SCREAMING-KEBAB-CASE
Two-Words	Train-Case, HTTP-Header-Case

Source: Naming Convention (Programming) on Wikipedia