defintions

Definitions are statements that assign meaning to terms or concepts and thereby aid clear communication. In a definition, the term being defined is called the definiendum, and the description that fixes its meaning is the definiens. A well-made definition should be precise, non-circular, and appropriate to the context, indicating both what the term includes and what it excludes.

Definitions can take several forms. Lexical definitions describe how a term is used in ordinary language, similar to dictionary entries. Stipulative definitions assign a meaning for a term in a particular discourse, regardless of prior usage. Precising definitions reduce ambiguity in a specific context, for example by narrowing a vague term like 'publicly available' in a contract. Theoretical definitions connect a term to a theory, defining it in terms of the theoretical role it plays. In mathematics and logic, definitions often specify necessary and sufficient conditions, as in "a prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself." Ostensive definitions identify the meaning by pointing to examples.

Definitional problems occur when definitions are circular (defining a term with itself), too broad or too narrow, vague, or culturally biased. Good definitions telegraph scope clearly and avoid ambiguity. Definitions are central to fields such as science, law, philosophy, and computer science, where precise terminology supports reasoning, classification, and communication. The practice of defining also raises methodological questions about how terms should be used and understood in different communities.