A non-native person who comes to a country from another country to permanently settle there.
A plant or animal that establishes itself in an area where it previously did not exist.
Of or relating to immigrants or the act of immigrating.
A person of no identity; a nonentity
A variable (usually x, y or z) whose value is to be found.
Any thing, place, or situation about which nothing is known; an unknown fact or piece of information.
Not known; unidentified; not well known.