The term 'Greek L's' refers to the Greek letter Lambda (Λ), which is the 11th letter of the Greek alphabet. Lambda is often used in mathematics, science, and engineering to represent various constants and variables. It is also used in chemistry to represent the wavelength of light. In addition, Lambda is used in physics to represent the angular momentum of a particle. In philosophy, Lambda is used to represent the concept of change or transformation. In religion, Lambda is used to represent the Christian Trinity.