The Collaborative International Dictionary of English v.0.48:

Micrococcus \Mi`cro*coc"cus\, n.; pl. Micrococci. [NL. See
   Micro-, and Coccus.] (Biol.)
   A genus of Spherobacteria, in the form of very small
   globular or oval cells, forming, by transverse division,
   filaments, or chains of cells, or in some cases single
   organisms shaped like dumb-bells (Diplococcus), all without
   the power of motion. See Illust. of Ascoccus.
   [1913 Webster]

   Note: Physiologically, micrococci are divided into three
         groups; chromogenic, characterized by their power of
         forming pigment; zymogenic, including those associated
         with definite chemical processes; and pathogenic, those
         connected with disease.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Micrococcus
    n 1: type genus of the family Micrococcaceae [syn:
         Micrococcus, genus Micrococcus]