= Z =
zeroth /zee'rohth/ adj.
First. Among software designers,
comes from C's and LISP's 0-based indexing of arrays. Hardware
people also tend to start counting at 0 instead of 1; this is
natural since, e.g., the 256 states of 8 bits correspond to the
binary numbers 0, 1, ..., 255 and the digital devices known as
`counters' count in this way.
Hackers and computer scientists often like to call the first
chapter of a publication `Chapter 0', especially if it is of an
introductory nature (one of the classic instances was in the First
Edition of K&R). In recent years this trait has also been
observed among many pure mathematicians (who have an independent
tradition of numbering from 0). Zero-based numbering tends to
reduce fencepost errors, though it cannot eliminate them
--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.