tautologous adjective (of a statement, etc.) saying the same thing twice in different words, when this is unnecessary, for example ‘They spoke in turn, one after the other.’ synonym tautologicaltautological adjective (of a statement, etc.) saying the same thing twice in different words, when this is unnecessary, for example ‘They spoke in turn, one after the other.’ synonym tautologous
re tannoyI think it's a trademark and probably should have a capital; however the same could be said for roneo and xerox and they are both allowed.
I think tannoy as a generic term meaning speakers may be peculiar to the UK - I know Tannoy as a manufacturer of speakers but, probably, only because I was interested in hi-fi in my youth...