noun a mass of type confusedly mixed or unsorted.
2. pi ·add. ·noun a greek letter (/, /) corresponding to the roman letter p.
3. pi ·vt to put into a mixed and disordered condition, as type; to mix and disarrange the type of; as, to pi a form.
4. pi ·add. ·noun specif.: (math.) the letter /, /, as used to denote the number or quotient approximately expressing the ratio of the circumference of a circle to its diameter; also, the quotient or the ratio itself. the value of the quotient pi, to eight decimal places, is 3.14159265. the quotient pi cannot be expressed as a root of an algebraic equation; and from this fact follows the impossibility of the quadrature of the circle by purely algebraic processes, or by the aid of a ruler and compass.