/el' k*-mee'noh big'nuhm/ The road mundanely called El Camino Real, a road through the San Francisco peninsula that originally extended all the way down to Mexico City and many portions of which are still intact. Navigation on the San Francisco peninsula is usually done relative to El Camino Real, which defines logical north and south even though it isn't really north-south many places. El Camino Real runs right past Stanford University.
The Spanish word "real" (which has two syllables: /ray-al'/) means "royal"; El Camino Real is "the royal road". In the Fortran language, a "real" quantity is a number typically precise to seven significant digits, and a "double precision" quantity is a larger floating-point number, precise to perhaps fourteen significant digits (other languages have similar "real" types).
When a hacker from MIT visited Stanford in 1976, he remarked what a long road El Camino Real was. Making a pun on "real", he started calling it "El Camino Double Precision" - but when the hacker was told that the road was hundreds of miles long, he renamed it "El Camino Bignum", and that name has stuck. (See bignum).