blood-tub
/ˈblʌdtʌb/noun
1A tub containing, or designed to contain blood; especially a tub employed in a slaughterhouse to hold the blood of slaughtered animals. Now also in extended use.
2 US History. Chiefly with capital initial(s). Usually in plural A member of a street gang based in Baltimore, Maryland, whose members made violent interventions in the elections of the 1850s and 1860s in support of the nativist cause; (also) a member of any of various similar gangs existing on the East Coast in the same period.
3 British. A familiar or colloquial name for: a theatre or cinema having a reputation for presenting violent or sensational material, especially lurid melodramas. Now historical.
Origin
Mid 18th century; earliest use found in Proceedings of the Old Bailey. From blood + tub.