Webster's Revised Unabridged Dictionary · 1913

Lucid

Lucid , adjective

[Latin lucidus, from lux, lucis, light. See Light, n.]

1.
Shining; bright; resplendent; as, the lucid orbs of heaven.
Lucid, like a glowworm. — Sir I. Newton
A court compact of lucid marbles. — Tennyson
2.
Clear; transparent.
Lucid streams. — Milton
3.
Presenting a clear view; easily understood; clear.
A lucid and interesting abstract of the debate. — Macaulay
4.
Bright with the radiance of intellect; not darkened or confused by delirium or madness; marked by the regular operations of reason; as, a lucid interval.