On the Ellis Island documents concerning my great grandparents Silesia is spelled Galicia.
Galicia is something different than Silesia. Galicia was part of the Austrian-Hungarian Empire, whereas Silesia was divided into these two countries in 1741 when Prussia conquered on Austria a major part of the Silesian territory including the capital Breslau/Wrocław. Thus, until the year 1918 we had the Prussian Silesia as well as the Austrian Silesia, or the region of Opava, which region was administratively separate from the land of Moravia. On top of this we had the Duchy of Cieszyn which was a separate administrative unit within Austria; it was a Silesian duchy, however, not to be confounded with the neighbouring Galicia.
The name of Galicia appeared after the first partition of Poland in 1772 when the Austrian called the grabbed territory by the name "Kingdom of Galicia and Lodomeria". Both names are latinized versions of Ruthenian [we now say: Ukrainian] names: Halichina and Vlodimiria. In the beginning the Austrians used to exploit the acquired territory enormously which made the Polish and Ruthenian populations inhabiting the kingdom nickname it as "Kingdom of Golicja i Głodomeria" which would translate into English as "The Kingdom of the Naked and the Hungry. Later on, the region was given a broad autonomy within the Habsburg Empire and became one where neither Polishness were persecuted nor the Polish language was eradicated from public use.