Lucid means perfectly clear in thought or explanation. A lucid account, lucid prose, a lucid moment.
Of writing it is high praise: lucid means the reader never has to go back a line. Of a person it means mentally clear, which is why it is used in medicine — a lucid interval, lucid at times — and often about somebody who is not always so. A lucid dream is one in which the dreamer knows they are dreaming. Note lucidity; and elucidate, which means to make clear.
1adjectivelucidPerfectly clear in thought or explanation.
“The teacher gave a lucid explanation that everyone understood.”
synonyms: clear, intelligible
2adjectivementallyMentally clear.
“Despite his illness, the old man was still lucid and knew everyone in the room.”
lucid is a quality of clarity.
Latin lucidus comes from lucere, to shine, from lux, light. Lucifer, translucent and elucidate come from the same light.
Proto-Indo-European
*lewk-
Latin
lūcidus
English, today
lucid
Built from
From Latin lūcidus. Latin lucidus, from lūceō (“shine”) + -idus.
Etymology from Wiktionary, CC BY-SA
Practised in Sharper Adjectives