A person who conveys orders, announcements, or messages, often in a military, official, or formal context.
The messenger conveyed the orders from headquarters to the front line.
中世の戦場では、伝令者が重要な役割を果たした。
On medieval battlefields, heralds played an important role.
Compound of 伝令 (order, message) + 者 (person). The exact historical derivation is uncertain, but the word follows a standard Sino-Japanese pattern for agent nouns.