The son of Ar-Zimrathôn and the 22nd ruler of Númenor, whose Quenya name was Tar-Falassion (UT/223). Tolkien didn’t translate either name, but his Quenya name seems to mean something like “Shore-son” (falassë “shore” + -ion* “-son”) and his Adûnaic name may have a similar meaning, as suggested by several authors (AAD/22, AL/Adûnaic, EotAL/SAK’L). If so, the initial element *sakal would mean “shore” and the suffix -thôr would mean “-son”.
The interpretation of the second element is less certain than the first. For example, Carl Hostetter and Patrick Wynne suggested (AAD/11) that is Quenya name Falassion is actually a genitive plural meaning “of the Coasts” and does not involve “-son” at all. They suggested the final -thôr may instead mean “one” or “lord” (AAD/23).