tannoy
Concise Oxford English Dictionary © 2008 Oxford University Press:
tannoy /ˈtanɔɪ/ Brit.
▶noun trademark a type of public address system. ▶verb transmit or announce over such a system.
– origin 1920s: contr. of tantalum alloy, which is used as a rectifier in the system.
'tannoy' also found in these Oxford entries:

