Find examples of the word in use. Google (and especially Google Books) are excellent resources for finding citations. Citations provide evidence that the word is in use and show how it is used. Examine how the word functions in the examples that you find. Determine the part of speech of the word, for the sense or senses you wish to define. This will help you write the right definition. Make further distinctions within the parts of speech. If you wish to be thorough about the grammatical function of this word, further determine whether a noun is countable or uncountable, whether a verb is transitive or intransitive, and so on. Choose a specific sense of the word and think about the word's meaning in that sense. One good way to go about this is to consider how you would explain this word to a small child or a person who is just beginning to speak the language. Avoid using descriptive words that are more complicated than the word in question, unless you also explain their meaning.
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