A plain garment covers a body. A garment with passementerie communicates.
The distinction sounds small until one considers what a single gold stripe on a sleeve has historically been able to say: the rank of the person wearing it, the institution they serve, the level of authority they carry into a room before they have spoken a word.
Passementerie began not as decoration in the modern sense but as a coding system, a way of making hierarchy legible at a glance in courts, armies, and churches where the wrong person giving the wrong order could cost lives. The braid was never merely beautiful. It was a statement of position, and everyone in the room knew how to read it.
That function has not disappeared. It has simply become so embedded in the visual grammar of formal dress that it is no longer consciously noticed, which is perhaps the most reliable sign that a language has truly taken hold.
image credit: M. Maurer