Φ

Symbol

 * 1)  an angle
 * 2)  golden ratio conjugate ≈ 0.618...
 * 3)  magnetic flux
 * 4) Phrateres, a non-profit social-service organization for women in North America
 * 5)  A wildcard for a pharyngeal consonant
 * synonyms: sometimes covered by H

Usage notes
This letter has multiple lowercase forms:
 * φ, the form normally used in Modern Greek;
 * ϕ, often used as a symbol for various things; or ɸ, the form properly used if denoting a (these two forms are, in many fonts, indistinguishable or nearly so; Times New Roman is one font in which they are clearly distinct).
 * 𝜙, sometimes used as a symbol.

Etymology
grc; possibly a modification of (koppa) as some cases of Ancient Greek  come from earlier.

Letter

 * 1) The letter phi, the 21st letter of the ancient Greek alphabet.

Letter

 * 1) The upper case letter phi (φι), the 21st letter of the modern Greek alphabet.