<u>Term 'Alien' in a legal sense refers to the person who is the resident of the foreign country while not being a proper lawful citizen of it.</u>
They can be
legal alien - have some kind of issued permit to be a resident of the country for a certain time, such as tourist visa, work permit, or another kind of document issued by the government
illegal alien - a non-recorded visitor who can even enter the country legally, but in the meantime fallen out of the legal framework of the resistance and keep staying in the country outside of boarders of law.
