De*vel"op*er (?), n.
1.
One who, or that which, develops.
2. (Photog.)
A reagent by the action of which the latent image upon a photographic plate, after exposure in the camera, or otherwise, is developed and visible.
© Webster 1913
De*vel"op*er, n.
One that develops; specif.:
(a) (Photog.)
A chemical bath or reagent used in developing photographs.
(b) (Dyeing)
A reagent used to produce an ingrain color by its action upon some substance on the fiber.
© Webster 1913