Pi - Definition

n 1: the ratio of the circumference to the diameter of a circle;
approximately equal to 3.14159265358979323846...
2: someone who can be employed as a detective to collect
information [syn: private detective, PI, private eye,
private investigator, operative, shamus, sherlock]
3: the scientist in charge of an experiment or research project
[syn: principal investigator, PI]
4: the 16th letter of the Greek alphabet
5: an antiviral drug used against HIV; interrupts HIV
replication by binding and blocking HIV protease; often used
in combination with other drugs [syn: protease inhibitor,
PI]