a low-level programming language that uses more memorable mnemonic codes and labels to represent machine-level code. each instruction corresponds to just one machine operation
- programming language closer to machine code  - uses mnemonics to refer to commands - directly related to machine code, refers to registry names in code
data that classifies observations without quantitative meaning (for example, colors of cars) or where quantitative amounts are categorized (for example, &"0-10, 11-20, ...&").