What is the meaning of diatom?

Diatoms:

1. The single-celled algae living in glass houses containing freshwater are known as diatoms.
2. The cell wall of diatoms is made up of transparent, opaline silica.
3. The cell wall is known as a frustule.
4. The cell wall of diatoms has two halves known as epitheca and hypotheca.
5. The two halves of the cell wall of diatoms are called epitheca and hypotheca.
6. Examples of diatoms: Chaetoceros, Cyclotella.