What are the pieces used to fill in a template called?
Solution 1:
You could refer to {firstname}, {booktitle} and {duedate} as placeholders or variables.
Solution 2:
Since you're obviously looking for an abstract term I would suggest parameter.
You could refer to {firstname}, {booktitle} and {duedate} as placeholders or variables.
Since you're obviously looking for an abstract term I would suggest parameter.