Slask vs Silesia

Slask and Silesia both are nouns.

Word	Noun	Adjective	Verb	Adverb
Slask	Yes	No	No	No
Silesia	Yes	No	No	No

As nouns, Slask and Silesia are synonyms defined as:

Slask and Silesia: a region of central Europe rich in deposits of coal and iron ore; annexed by Prussia in 1742 but now largely in Poland

Other synonyms of Slask include Schlesien, Slezsko.

Slask (noun)	Silesia (noun)
a region of central Europe rich in deposits of coal and iron ore; annexed by Prussia in 1742 but now largely in Poland	a region of central Europe rich in deposits of coal and iron ore; annexed by Prussia in 1742 but now largely in Poland