Historical term for a Chinese person, especially in pre-modern contexts. In modern usage, 中国人 is the neutral term.
In the Edo period, Chinese people stayed in Dejima, Nagasaki.
Archaic broad sense for any foreigner, not limited to Chinese. Rarely used today.
In old documents, the word 唐人 sometimes broadly referred to foreigners.
damn Westerner; hairy foreigner
From 唐 (Tang dynasty) + 人 (person). Originally referred to people from Tang China, later extended to Chinese people in general and, archaically, to any foreigner.