Phi (Greek Letter)

	Main Article	Discussion	Related Articles  [?]	Bibliography  [?]	External Links  [?]	Citable Version  [?]
	This editable Main Article is under development and subject to a disclaimer. [edit intro]

Phi is the 21st letter of the Greek alphabet. It is written as ${\displaystyle \Phi }$ (upper-case) and ${\displaystyle \phi }$ (lower-case).