Tzamourthis

My father Nicholas Cassimaty who came from Kato Livathi migrated to Australia in 1922. He had a brother George who lived in New York, Spiro, Emmanuel and Panayioti (who lived in Australia), sisters, Maria Callegeros and Chrisoula Paspalas (who lived in Kythera) and Stavroula Samios who lived in Australia.

The family parachoukli is "Tzamourthis". I'm unsure of the derivation of this nickname can anyone enlighten me?

Also my Uncle George Cassimatis left for New York before my father was born in 1904.
He passed away in 1958. Can anybody furnish me with any information/photos about his life in the USA?