We can separate groups of tables into their own "namespaces", referred to as "schemas" by PostgreSQL. In many ways, they can be thought of as being similar to directories, though that is not a precise description.
Make sure you've read the Deciding on a design for multitenancy recipe so that you're certain that this is the route you wish to take. Other options exist, and they may be preferable in some cases.
CREATE SCHEMA finance; CREATE SCHEMA sales;
CREATE TABLE finance.month_end_snapshot (.….)
The default schema in which an object is created ...