alien / foreigner / stranger ---A stranger is a person you don't know: When I was a child, my mother taught me not to get into a car with a stranger. When my car broke down, a kind stranger stopped to help me. ---A foreigner is someone who comes from another country: This town is a popular tourist destination, so there are always a lot of foreigners around. The new law makes it easier for foreigners to get documents to work legally. A lot of foreigners have been moving into this neighborhood – I’ve met people from seven different countries in my apartment building alone! ---The word alien is a legal term for foreigner. It is usually used to describe "illegal ---aliens" (people who are in the country illegally) or "resident aliens" (people who are living in the country legally). Again, this is formal/legal language and in everyday speaking it's best to use foreigner. ---Alien also refers to creatures from other planets; it is another word for extraterrestrial