Visitor, visitant, guest, caller mean one who visits another or comes to pay a visit.
Visitor is the general word applicable to anyone who comes under this description, but it is especially applicable to one who makes a friendly visit or one who comes in the cause of charity, social service, or investigation.
Visitant is applied especially to a visitor who is or seems to be from another sphere (as heaven or hell).
As compared with visitor , guest emphasizes the idea of hospitable entertainment; it applies therefore chiefly to one who comes as a result of an invitation.
It also is often used, sometimes in the expanded form paying guest , of a lodger or boarder, and is used regularly for patrons of a restaurant or hotel.
Caller is applicable not only to one who comes for a social or business call (see under VISIT ) but to anyone regardless of his intentions who seeks entrance to one’s home or office.