when I use the words "Cup" and "glass"?
segundo o que eu entendi, as duas significam copo, mas ainda não entendo quando se usa ou em qual situação se usa uma ou outra. obrigado.
according to what I understand, the two mean glass, but still do not understand when using or in what situation using either. thank you.

Question

Answer

a cup has a handle and is made of pottery, or ceramics -it is used for drinking hot liquids
a glass has no handle, but is held by the stem, or base and is used for cold liquids.
Note:  this is the modern usage.  Historically, any vessel used to hold liquid for drinking could have been referred to as a cup.

Answer

Glass is used when the container is made of the material glass (or looks a lot like it is), usually these are a bit longer and contain cold liquids.
Cup is used for containers made from other materials, usually they are shorter and they're more often used for hot beverages like tea or coffee.

Try typing both into Google image search, you'll see the difference immediately.