A pooled table is a special type of table available in the SAP ABAP dictionary. The pooled table is a proprietary SAP creation and has many-to-one relationships with tables in the SAP database. This means that for a given pooled table in the database, there could be many smaller tables in the SAP data dictionary. SAP uses pooled tables for integrating and holding a large number of small tables. This helps in reducing the space and resources needed at the database level. SAP mostly uses pooled tables for maintaining system data.
Techopedia explains Pooled Table
A pooled table can have a different name at the database than the one in the ABAP dictionary. It can also have a different number of fields and the field names can be different as well. Pooled tables can hold a large number (thousands) of smaller tables, which can have between 10 and 100 rows. All key fields of a pooled table must also have character data types.
Users are allowed to create pooled tables. For this purpose, first the definition of the pooled table has to be defined in the data dictionary. After activating the pooled table definition, associated single tables can be created in the database. For finding pooled tables in a given SAP system, transaction se11 or SE14 can be used.