A form prepared for filling — structure decided once so content can be many. The template is the hearth-side of repetition: sameness where sameness serves.
French templet, a diminutive of temple (a weaver's stretching device), traced to Latin templum in its sense of a small piece of timber; a form prepared once so content could be repeated many times over a loom, long before it named a document.
A form prepared once, so structure can be decided a single time and content can be many. The hearth-side of repetition, sameness kept exactly where sameness serves.