1. transmitting messages or signals using a heliograph (a device that reflects sunlight to send coded messages over long distances)
Usage: present participle of heliograph; historical/military context; technical
2. photographing or recording using a heliograph or early photographic process
Usage: archaic; photography history

Examples

• The soldiers were heliographing messages across the valley using mirrors and sunlight.
• During the 19th century, military units relied on heliographing to communicate over vast distances.
• The operator spent hours heliographing coordinates to the distant outpost.
• Before radio technology, heliographing was an essential communication method in remote areas.
• The team practiced heliographing signals to ensure clear transmission in daylight conditions.