We can only add one definition at a time, and adding secondary definitions require completely new workflows. For this reason, term definitions are (for the lack of a better phrase) made to order. That is, we enter definitions according to need. For this reason we may have to update a term’s definition or add a new definition in the future. This will likely be the case until an option is provided to add multiple definitions at once.
To add a new definition to an existing term (without changing an existing definition), when asked if you want to use any of the existing definitions, select No, and a new text box will spawn. Here is where you will enter your new definition.