mach.lon is the personal name of a man identified as Naomi's son, Ruth's deceased husband, and an heir whose name is to continue.

The term is used consistently as a proper personal name: it identifies one of Naomi's sons, later described as deceased and as Ruth's husband, whose name is connected with inheritance in the cited clauses.

1. Personal name in family and inheritance clauses · dominant

   The form is tagged Noun · Proper in every occurrence. In Ruth 1:2 the APB renders the clause as naming Naomi's two sons, “Mahlon and Chilion”; in Ruth 1:5 it identifies one of the two sons who died. In Ruth 4:9 and Ruth 4:10, the name occurs in statements about property, Ruth as his wife, and preserving the deceased man's name upon his inheritance.

   Ruth 1:2Ruth 1:5Ruth 4:9Ruth 4:10

In the Anselm Project Bible: The APB presents the term as “Mahlon” in family, death, property, marriage, and inheritance clauses. These clauses confirm the personal-name use rather than supplying a lexical translation.