Classification is a process by which items are organized according to certain criteria. This is prevalent in the sciences. For instance, in biology, particularly in taxonomy, living organisms are classified into taxons.
In real life, we always see classification.
- Food sold in market. These can be classified in different ways: cold vs. hot, imported vs. local. Food sold in the market can also be classified depending on their kind: junk food, condiments, fruits, vegetables, breakfast, etc.
- Money is also classified as M0, MB, M1, M2, M3, or MZM. This classification is based on the liquidity of money, and depends on the government. For instance, M0 is for bank reserves, while notes and bank coins in vaults are classified under M1.
- TV shows are classified based on their genre. There are scifi, sitcom, romcom, etc.
- Cars are classified based on their performance or size. For instance, some classifications are sports (high performance), luxury (high end cars), large, midsize, and small (based on size).
- Petroleum is classified in the industry depending on the source. By source, these can be classified as West Texas, Intermediate, Brent, or Oman. It may also be classified as light vs. heavy (depending on density) or sweet vs. sour (depending on sulfur content).