heliogram
he·liog·ram
noun
1.
a message transmitted by means of the sun''s rays
Origin
From helio- + -gram.
Related words
Broader terms
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.