When you are in an odd-numbered person situation and everyone else pairs off to do something fun (usually sex) and you're left by yourself on the couch to watch t.v., play video games, eat leftovers, do something not as fun as everyone else. In horror movies, this character is usually the first one to die to demonstrate how the monster works.

The safeguarding of Earth and other worlds from biological cross-contamination (i.e. billionaires with too much time on their hands).

Also known as “planetary protection.” Planetary protection / quarantine “reflects both the unknown nature of the space environment and the desire of the scientific community to preserve the pristine nature of celestial bodies until they can be studied in detail.”

There are two types of interplanetary contamination. Forward contamination is the transfer of viable organisms from Earth to another celestial body. Back contamination is the transfer of extraterrestrial organisms, if such exist, back to the Earth's biosphere.

A room mate that holds no job but has a lot of money in a bank account, like he/she got a huge settlement from being hit from a car or a rich uncle died.