From FinnegansWiki
A prehistoric structure consisting of two large stones set upright to support a third on their tops, found especially in Europe.
Also, the ancient name for three 1000 tonne stone blocks at the base of the temple at Baalbek in Lebanon.
The "meant to be baffling chrismon trilithon sign" (p.119) of a 90 degree clockwise E for Earwicker might be seen then as a trilithon such as are found at Stonehenge with an additional middle appendage.
