The Collaborative International Dictionary of English v.0.48:

Ocher \O"cher\, Ochre \O"chre\, n. [F. ocre, L. ochra, fr. Gr.
   ?, from (?) pale, pale yellow.]
   1. (Min.)
      (a) A impure earthy ore of iron or a ferruginous clay,
          usually red (hematite) or yellow (limonite), -- used
          as a pigment in making paints, etc. The name is also
          applied to clays of other colors.
      (b) A metallic oxide occurring in earthy form; as,
          tungstic ocher or tungstite.
          [1913 Webster]

   2. The color of ocher[1], varying around orange, from more
      yellowish to more reddish in tint.
      [PJC]

WordNet (r) 3.0 (2006):

ocher
    adj 1: of a moderate orange-yellow color [syn: ocher, ochre]
    n 1: a moderate yellow-orange to orange color [syn: ocher,
         ochre]
    2: any of various earths containing silica and alumina and
       ferric oxide; used as a pigment [syn: ocher, ochre]