Diatom /(dī`ȧ*tŏm)/

Di·a·tom

Diatom

n.
  1. One of the Diatomaceæ, a family of minute unicellular Algæ having a siliceous covering of great delicacy, each individual multiplying by spontaneous division. By some authors diatoms are called Bacillariæ, but this word is not in general use. (Bot.)
  2. A particle or atom endowed with the vital principle.
    The individual is nothing. He is no more than the diatom, the bit of protoplasm.