User:DCDuring/How I write definitions/General principles

Here are notes on generalizations about writing definitions that emerged when I was writing about defining words that fell into the various parts of speech.

Substitutability
For open-class terms, every attempt should be made to write a definition that can be substituted for the term to yield an intelligible result. A failure to do so may indicate a badly written definition (wrong PoS, etc) or a definition that does not cover all uses of a polysemic word.

If one cannot write a definition of a term that can be substituted, it may be clear that additional definitions are needed. In some cases no substitutable definition that also meets other desiderata for a definition can be found. In such cases a "non-gloss definition" may be required. This is usually true for basic function words and certain kinds of idioms, that serve purposes such as greeting, taking leave, discourse "control" or coordination, and various others.