Pi

;Astronomical nomenclature
* Pi Canis Majoris, a star in the Beta Quadrant
* Pi³ Orionis, a star
* Pi Hydrae, a star system
* Pi Piscis Australis, a star system
;Command codes
* "Barclay-pi-3", used to transfer controls to hologrid program
* "Janeway-pi-1-1-0", used to initiate/terminate self-destruct sequence and as a command override
* "Janeway-pi-alpha"
* "Pathway-pi-2", a computer pathway on a Borg cube
* "Tuvok-pi-alpha", a security override to enter another's quarters
;Mathematics
* Pi (number), the mathematical term
;Production reference
* Antares Pi IV, an unreferenced planet
;See also
* Pi (starship), a Romulan scout ship
* PI, abbreviation and slang for a private investigator
* Pie, a typically delicious dessert
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