[ 'trʌn(t)ʃ(ə)n ]
■ noun chiefly Brit.
1》 a short thick stick carried as a weapon by a police officer.
2》 a staff or baton acting as a symbol of authority, especially that used by the Earl Marshal.
Origin
ME (denoting a piece broken off, also a cudgel): from OFr. tronchon 'stump', based on L. truncus 'trunk'.