glass
In German, the word for glass is 'Glas'. It is a neuter noun and can refer to both drinking glasses and glass as a material. For example, 'Ich trinke aus einem Glas' means 'I drink from a glass'. When referring to glass as a material, 'Das Fenster ist aus Glas' means 'The window is made of glass'.
I drink water from a glass.
This sentence is an example of using 'Glas' to talk about drink containers. It is a common usage where 'Glas' refers to a drinking utensil, similar to how 'glass' is used in English.
The glass is half full.
This phrase is often used as a metaphor to describe an optimistic point of view. The 'Glas' here represents a container, and the phrase itself highlights the German usage of 'Glas' to denote the same.
Be careful, the glass is very thin.
This phrase uses 'Glas' to refer to a material. Much like in English, the word 'Glas' is used in German not only to refer to certain drinking utensils but also to the material these are commonly made of.