Adding new terms to memoQ term bases typically happens using the Add Term or Quick Add Term commands (default keyboard shortcuts: Ctrl+E and Ctrl+Q respectively) found in the Store group on the Translation, Review and Quick Access ribbons in a memoQ project:

But where do those terms actually go? When a memoQ project is created, one term base is designated as the "target" or destination for new words and their translations to be added. The line for that term base in the list is shown in bold type.

The term base designated as the target for new terms can also be changed in the opened project. This can be done in several ways. If you go to Project home > Term bases, the Term Bases resource ribbon will be shown, and there in the Project group, a different term base can be selected and set as the target for new terms.

But... you can also have more than one term base set as a target for new terms that you add while working in the project. This is done in the Add Term dialog:

In the example shown above, the new term (German "Zielhafen" and English "destination harbor") will be written to three different term bases with marked checkboxes in the dropdown list of project term bases at the top of the dialog. If a term is already in any of the selected term bases, the Duplicates tab of the dialog will indicate the possible redundancy and provide more information.

After multiple term bases have been designated in the Add Term dialog as the default targets for new terms, when you use the Quick Add Term command, the new term will be added to all three selected term bases.

Note that for Quick Add Term, both a source language term and a target language term must be selected or the command is disabled. For the Add Term dialog to be invoked, source and target side terms can be selected, but the command will also work if a term is selected on only one side or even if no term is selected at all. Selected terms are copied as entries in the dialog, and any number of new entries (for synonyms or forbidden terms, for example) can be made on both source and target sides. Thus the Add Term command can be used to enter new terms which might not even appear in the source text!