-
(n) pi: (the ratio of the circumference to the diameter of a circle; approximately equal to 3.14159265358979323846...)
-
(n) pi: (the 16th letter of the Greek alphabet)
-
(n) principal_investigator, PI: (the scientist in charge of an experiment or research project)
-
(n) private_detective, PI, private_eye, private_investigator, operative, shamus, sherlock: (someone who can be employed as a detective to collect information)
-
(n) protease_inhibitor, PI: (an antiviral drug used against HIV; interrupts HIV replication by binding and blocking HIV protease; often used in combination with other drugs)