What is Sailor?

Legal Definition
A sailor, seaman, mariner, or seafarer is a person who navigates waterborne vessels or assists as a crewmember in their operation and maintenance. The term bluejacket may be used for British or US Navy enlisted sailors, the latter especially when deployed ashore as infantry. The Bluejacket's Manual is the basic handbook for United States Navy personnel. 700,000 of the world's mariners come from the Philippines, being the world's largest origin of seafarers.

Etymologically, the name "sailor" preserves the memory of the time when ships were commonly powered by sails, but it applies to the personnel of all vessels, whatever their mode of propulsion, and includes military (naval) and security (coast guard) maritime personnel and members of the merchant marine, as well as recreational sailors. The term "seaman" is frequently used in the particular sense of a sailor who is not an officer.
-- Wikipedia
Legal Definition
Seamen, mariners. Vide Mariners; Seamen; Shipping Articles.
-- Bouviers Law Dictionary
Legal Definition
Seamen; mariners.
-- Black's Law Dictionary