heliograph

Từ điển Oxford Learners Wordfinder Dictionary

I - noun

an apparatus for sending telegraphic messages by using a mirror to turn the sun's rays off and on
• Hypernyms:
apparatus, setup

II - verb

signal by means of a mirror and the using the sun's rays
• Hypernyms:
sign, signal, signalize, signalise
• Verb Frames:
- Somebody ----s something
- Somebody ----s that CLAUSE