fire cross
/ˈfʌɪə krɒs/Now historical
noun
A piece of wood, charred and dipped in blood, used among Scottish clans as a signal to summon men to arms.
- To ensure that the summons reached everyone in a short amount of time, the fire cross was relayed at speed from one appointed clansman to another until the whole district had been covered..
Origin
Early 16th century; earliest use found in Acts of Lords of Council in Civil Causes. From fire + cross.