a. Emitting light, especially in the dark; shining.
b. Reflecting light; illuminated: "He watched a luminous cloud drifting up from the Gulf" (Tim Gautreaux). See Synonyms at bright.
2. Having a high degree of saturation: a luminous green.
a. Presented or perceived clearly or vividly: luminous memories.
b. Enlightened or intelligent: luminous ideas.
[Middle English, from Old French lumineux, from Latin lūminōsus, from lūmen, lūmin-, light; see leuk- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.
American Heritage Dictionary Products
The American Heritage Dictionary, 5th Edition
The American Heritage Dictionary of Idioms
The American Heritage Roget's Thesaurus
Curious George's Dictionary
The American Heritage Children's Dictionary
The American Heritage Dictionary of Indo-European Roots
The American Heritage Student Grammar Dictionary
The American Heritage Desk Dictionary + Thesaurus
The American Heritage Science Dictionary
The American Heritage Dictionary of Business Terms
The American Heritage Student Dictionary
The American Heritage Essential Student Thesaurus