The GRE is a long, serious test that people take when they want to go to graduate school — more study after a first university degree. The letters stand for Graduate Record Examinations. Students in the US sit it a lot, but students in Taiwan take it too if they hope to do a master's or a PhD in the US, and in some other countries. It does not ask “can you speak English?” so much as “can you read hard text, handle numbers, and build an argument in writing?” Though actually it is not one single paper for every subject: the main one is the General Test, and there used to be extra subject tests for things like physics or literature. People talk about a GRE score the way they talk about a gate you have to pass. Some schools still want it very much; some have stopped asking for it. It feels formal and a bit frightening, and it is easy to mix up with other tests that are not the same job.