What does “rayon” mean in a French supermarket?

In a French shop un rayon is an aisle or a department: le rayon boulangerie, le rayon frais. Staff say j’étais en rayon for “I was out on the shop floor,” and un chef de rayon is a department manager. It is the very same word as a ray of sunlight and a spoke of a wheel — all of them things radiating outwards from a centre.

Elsewhere: un rayon de soleil (a sunbeam), les rayons X (X-rays), dans un rayon de dix kilomètres (“within a ten-kilometre radius”), and the idiom ce n’est pas mon rayon — “that’s not my department,” used far outside actual shops. The clip opens with an employee reporting exactly the retail sense: j’étais en rayon et y a ce monsieur qui teste les salades.