The Collaborative International Dictionary of English v.0.48:

Developer \De*vel"op*er\, n.
   1. One who, or that which, develops.
      [1913 Webster]

   2. (Photog.) A chemical bath or reagent used in developing
      photographs.

   Note: By the action of the developer, the latent image on a
         photographic plate or film, not perceptible to the eye
         after exposure in the camera, is developed and becomes
         visible.
         [1913 Webster +PJC]

   3. (Dyeing) A reagent used to produce an ingrain color by its
      action upon some substance on the fiber.
      [Webster 1913 Suppl.]

   4. a corporation or individual who finances or organizes a
      real estate development[5].
      [PJC]

WordNet (r) 3.0 (2006):

developer
    n 1: someone who develops real estate (especially someone who
         prepares a site for residential or commercial use)
    2: photographic equipment consisting of a chemical solution for
       developing film

The Free On-line Dictionary of Computing (19 January 2023):

developer

   programmer


The Free On-line Dictionary of Computing (19 January 2023):

developer

        A member of the Debian project.