Source : Webster's Revised Unabridged Dictionary (1913)

Bacteroid \Bac"te*roid\, Bacteroidal \Bac`te*roid"al\, a.
   [Bacterium + -oid.] (Biol.)
   Resembling bacteria; as, bacteroid particles.

Source : WordNet®

bacteroid
     n : a rodlike bacterium (especially any of the rod-shaped or
         branched bacteria in the root nodules of nitrogen-fixing
         plants)

bacteroid
     adj : resembling bacteria [syn: {bacteroidal}, {bacterioidal}, {bacterioid}]