The city of Taunton is very multi-cultural with peoples of different origins living within the city. 34% of the city is Luso-American. The biggest ethnic backgrounds people claim are 23% Portuguese,17% Irish, 9% English, 9% French, 8% Cape Verdean and 4% Puerto Rican.
https://en.wikipedia.org/wiki/Taunton,_Massachusetts
Luso-American are Portuguese. That explains the rather large Cape Verde sub group as well.
Never heard the expression before.
Looked it up and refers to Portuguese-Americans.
The term 'Luso' come from 'the Roman province of Lusitania, roughly corresponding to modern Portugal'.