(2 rows)

Wait, back up: What are tablespaces? That's PostgreSQL's name for the physical storage locations of your database objects on disk. In other words, they're plain old directories on your filesystem. So you can control your disk layout and put your database objects wherever you like; for example, you could put a heavily-used index on a fast disk, or move objects to another partition or disk if you run out of space. Postgres has a squillion built-in objects, such as tables, functions, data types, aggregates, operators, and views. It also supports user-created objects. You can see the objects in the postgres DB, as this abbreviated example shows:

postgres=# \ddS

Object descriptions