As nouns the difference between pi and tau
is that pi
is the name of the sixteenth letter of the Classical and Modern Greek alphabets and the seventeenth in Old Greek while tau
is the name of the letter Τ/τ in the Greek, Hebrew and ancient Semitic alphabets, being the nineteenth letter of the Classical and Modern Greek, the twenty-first letter of Old and Ancient Greek.
As a verb pi
is to spill or mix printing type. Also, "to pie".
As an adjective pi
is not part of the usual font character set; especially, non-Roman type or symbols as opposed to standard alphanumeric Roman type.
As an abbreviation pi
is pica (conventionally, 12 points = 1 pica, 6 picas = 1 inch.
As an initialism PI
is initialism of partial induction|lang=en see AI.