Mathematical Italic Phi Symbol

In HTML, write 𝜙 to enter this exact character.

Traditional TeX math uses \phi for the straight phi form and \varphi for the loopy form; those commands typeset glyphs and do not guarantee this exact Unicode character.

What does 𝜙 mean in math?

It is the italic mathematical form of Greek phi symbol ϕ.

In math formulas, it usually labels a variable; the equation supplies what that variable represents. The Greek alphabet adapted an earlier Phoenician writing system, then added phi for an aspirated “p”—a p followed by a puff of breath. The oldest known inscription in Greek letters dates to about 740 BCE. Ancient Greek used uppercase letters; today’s lowercase phi grew from cursive handwriting in the Middle Ages and Renaissance. In Modern Greek, φ is pronounced like English “f.”

The origin of phi’s shape is debated. One proposal links it to qoppa, an older Greek letter, but scholars dispute the link because the letters had different sound values. In Unicode’s math alphabets, 𝜙 corresponds to ϕ; the separate italic form 𝜑 corresponds to Greek letter φ. The font used may draw the outlines differently or lack a math glyph, so an outline alone may not identify the encoded variant.