by "database" do you mean "file"? Do you want to put all of these tables in a single file?
In the file where you want to bring in the table from another file, select Import Records | File from the file menu. Select the file from which you want to import and select the table within that file that you want to import. Then, in the field matching dialog that next pops up, select "new table" in the target table drop down. This import will then create a new table in your file with the same field definitions as the original and import the data in that table into the file.
This does not bring in any layouts, scripts, value lists, or relationships that you may have defined. Scripts can be imported. Layouts can, with care, be copied and pasted, but relationshps and value lists pretty much have to be recreated by hand in the target file.
FileMaker Advanced users can also copy and paste a table--which copies and pastes an empty table definition--leaving behind any data in the original table.
And you can leave the table in its separate file and use an external data source reference to create a new Tutorial: What are Table Occurrences? to a table in that file in Manage | Database | Relationships. Then the file where you set up that table occurrence can refer to data in your other file just as though both tables are in the same file.
Thank you so much PhilModJunk!