Origin of the word
comp card
[ˈkɒmp kɑːd] · noun · plural: comp cards · short for composite card
A double-sided card, usually A5, that answered on as little space as possible how someone looks, how tall they are and under which number they can be booked. One portrait on the front, a handful of looks on the back. That is where the name comes from: the composite.
That was the 1960s, when agencies kept their models in filing cabinets. Today a comp card is a set of digital files — for your directory profile, for social media, for your own site. That is what you get from me: retouched images in the sizes you need.
The word itself is a small mess. In German-speaking markets almost nobody says comp card. There it is a Sedcard, after Sebastian Sed, who sold the cards under that name in the 1960s. In the US you will also hear zed card, because Sed was often pronounced as Zed.
The German spelling Setcard, with a t, is a typing error that went on to have a remarkable career. It looks like it comes from the film set. It does not. Equally persistent is the theory that sed is short for seduce. Charming, but wrong.
Short version: comp card, composite card, sed card, sedcard, zed card, setcard and model card all mean the same thing. It used to be a piece of cardboard, today it is a set of files.