The Collaborative International Dictionary of English v.0.48:

Boustrophedon \Bou`stro*phe"don\, n. [Gr. ? turning like oxen in
   plowing; ? to turn.]
   An ancient mode of writing, in alternate directions, one line
   from left to right, and the next from right to left (as
   fields are plowed), as in early Greek and Hittite.
   [1913 Webster]

WordNet (r) 3.0 (2006):

boustrophedon
    n 1: an ancient writing system: having alternate lines written
         in opposite directions; literally `as the ox ploughs'

The Jargon File (version 4.4.7, 29 Dec 2003):

boustrophedon
 n.

    [from a Greek word for turning like an ox while plowing] An ancient method
    of writing using alternate left-to-right and right-to-left lines. This term
    is actually philologists' techspeak and typesetters' jargon. Erudite
    hackers use it for an optimization performed by some computer typesetting
    software and moving-head printers. The adverbial form ?boustrophedonically?
    is also found (hackers purely love constructions like this).