The Collaborative International Dictionary of English v.0.48:
Solomon's seal \Sol"o*mon's seal\
A mystic symbol consisting of two interlaced triangles
forming a star with six points, often with one triangle dark
and one light, symbolic of the union of soul and body. It is
shaped identically to the hexagram and Star of David,
distinguished only in its usage.
[Webster 1913 Suppl. +PJC]