Happy "Pi Day!"
Today is March 14, or 3/14, which echoes the famous number "pi" (3.14159265...). According to the Oxford English Dictionary (available from the Library's databases page), pi is best understood as being "equal to the ratio of the circumference of a circle to the diameter." That is, measure the distance around the circle (the circumference) and divide it by the distance across the circle (the diameter), and you'll always get the number pi. It's most famous for having an infinitely long string of digits after the decimal point, which various memory and computer experts pride themselves on memorizing or calculating as far as they can. Truth be told, any "irrational number" has the same endless characteristic, but pi holds a special place in our collective imaginations. For more information about pi and its history in both math and society, visit the International Pi Day site (be patient, it seems a bit overloaded today!) or read these interesting reference articles from Answers.com and this archived article from The Straight Dope.