Di"a*tom (?), n. [Gr. cut in two. See Diatomous.]
1. Bot.
One of the Diatomaceae, a family of minute unicellular Algae having a siliceous covering of great delicacy, each individual multiplying by spontaneous division. By some authors diatoms are called Bacillariae, but this word is not in general use.
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.
Mrs. E. Lynn Linton.
© Webster 1913.