ETYM Old Fren. alien, Latin alienus, from alius another; properly, therefore, belonging to another. Related to Else.
1. Being or from or characteristic of another place or part of the world; SYN. exotic, strange.
2. Not contained in or deriving from the essential nature of something; SYN. foreign.

1. A person who comes from a foreign country; someone who does not owe allegiance to your country
2. Anyone who does not belong in the environment in which they are found
3. A form of life assumed to exist outside the Earth or its atmosphere

In law, a person who is not a citizen of a particular nation.
In the US, federal legislation determines which aliens may legally enter a country or reside in it; their rights at law, both civil and criminal; and the processes and conditions by which they may become citizens.

1. Transfer property or ownership
2. Arouse hostility or indifference in where there had formerly been love, affection, or friendliness