Creating a TYPE that is an Array within a Function (or a predefined Array TYPE) in PostgreSQL

I am researching migration of a major system from Oracle to PostgreSQL. Getting into coding functions now, and am looking to see if there is a compatible object in PostgreSQL where, dynamically within a Function I can create a TYPE as an array. The syntax in Oracle is: TYPE VAR_STRING IS VARRAY(10) VARCHAR2(30); This creates a 10 element array TYPE named VAR_STRING to hold 10 strings of 30 characters. I am playing with PG 9.6, and even in the Create Type dialog, it is not obvious to me to make a pre-defined TYPE that can be an array.