Is there another word for glass, like denim is to jeans?

There is for glass as in a drinking glass such as  goblet, tumbler, cup, but I know of none that refer to glass as a material in the way that the words denim and jeans are used and even here jeans refers to a pair of pants or clothing made from denim such as a pair of jeans or a jean jacket, for example, and thus even these two terms are not totally synonomous.

Umm a cup?

Silica?  Crystal?
I'm not sure in what way you mean.

Cup,mug

Fused silicates with soda,lime, etc...
Torched sand maybe..
Transparent stuff that is brittle...lol.
Or, just call it by a foriegn name...like say it in a different language other than english...
I really can't tell you!   What to call it...surry..lol.. He he he.