The term PI DAY CELEBRANT, PERHAPS can be summarized as a NERD, which is a four letter word. Pi Day is an annual celebration of the mathematical constant pi (π) and is observed on March 14th (3/14 in the month/day format). A Pi Day celebrant, perhaps, is someone who celebrates this day, usually by participating in activities related to mathematics or eating pie. This person is often referred to as a NERD, which is a slang term for someone who is highly intelligent and socially awkward.