Psi Symbol
About Psi Symbol
ψ is the Psi Symbol, the lowercase form of the 23rd letter of the Greek alphabet (Ψ / ψ). The Psi Symbol ψ is among the most common Greek letters in scientific and technical literature, frequently used for In quantum mechanics it represents the wave function and is also used in psychology and related fields.
【Pronunciation】 In English, ψ is most often pronounced SIE or PSEE (IPA: /saɪ, psiː/). This is simply the anglicized name of the Greek letter.
The lowercase Psi Symbol ψ is written as a distinct Greek glyph and is assigned codepoint U+03C8 in the Greek and Coptic Unicode block. In plain or sans-serif fonts it can be mistaken for the Latin letter y, so verify the typeface or context.
【Historical Origin】 Psi derives from the Phoenician letter pe and is most famous in modern physics as Schrödinger's wave function.
【Common Uses】 ψ is highly active across disciplines: In quantum mechanics it represents the wave function and is also used in psychology and related fields. It often appears alongside the uppercase Sigma Σ and lowercase Sigma σ in formulas, papers, and engineering drawings.
How to Type Psi Symbol
Windows Input
Method 1: Hold Alt and type 968 on the numeric keypad, then release Alt to get ψ.
Mac Input
Method 2: Press Control + Command + Space to open the Character Viewer, search for 'greek' or 'Psi Symbol', then select ψ.
HTML/CSS Input
Method 3: HTML: ψ or ψ or ψ; CSS: content: "\03C8";
LaTeX Input
Method 4: Use the \psi command in LaTeX math mode to produce ψ.
Psi Symbol FAQ
How is ψ pronounced?
The English pronunciation of ψ is SIE or PSEE (IPA: /saɪ, psiː/). It is the anglicized name of the Greek letter, used directly rather than described as 'lowercase ψ'.
What is the difference between ψ and the Latin letter y?
ψ (U+03C8) is a Greek lowercase letter, whereas y is a Latin letter; their codepoints and glyphs differ. In a proper typeface ψ and y are clearly distinct, but in plain text or sans-serif fonts they can be confused, so rely on context.
How do I type ψ in Word, web pages, and LaTeX?
On Windows use Alt+968 on the numeric keypad; on Mac open the Character Viewer and search 'greek' or 'Psi Symbol'; on the web use the HTML entity ψ; in LaTeX use \psi. For bulk use, copy ψ directly from this page.