What ∏ means
Multiply every term the indices select. In ∏ᵢ₁ⁿ aᵢ, the small i is a counter. It runs from 1 up to n, so the expression means a₁ a₂ … aₙ. The product sign packs a long chain of multiplications into one operator and states the range exactly. For example, n! (n factorial) is the product of k for k from 1 to n.
Who introduced the sign is disputed. One account credits René Descartes, while the historian Florian Cajori points to Carl Friedrich Gauss's use in 1812. The sign was developed as a partner to Σ, the notation for repeated addition.
Formal mathematical notation. Writing it signals indexed multiplication inside a formula.
Part of collections
Don't confuse it with
2Combination ideas
3Questions people ask
1Why does ∏ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type or find ∏
- Also called
- product sign · product operator · big pi
- Search it as
- prod · pi product notation · capital pi product
- Shows up in
- Anything that takes text · its shape is whatever your font draws
∏\220FCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.








