Graphology - the study of handwritings; autograph - written with one's own hand; seismograph - a machine noting strength and duration of earthquakes. marina - a harbor for pleasure boats; maritime - relating to the sea; submarine - an undersea boat; aquamarine - color of sea water.
Chemicals are classified into various hazard classifications in accordance with their physiochemical properties and health hazards. Each class of chemical has a pictorial symbol called a danger symbol.
Chemical classes are groupings that relate chemicals by similar features. Chemicals can be classified by their structure (e.g., hydrocarbons), uses (e.g., pesticides), physical properties (e.g., volatile organic compounds [VOCs]), radiological properties (e.g., radioactive materials), or other factors.