What are we doing when we ask for the "definition" of a word? What are we looking for? —Often we’re looking to “make sense” of a sentence that contains an unknown word in it. So we might ask, “what does this word mean?” But, with a word like “hammer,” (something that seems simple to define), we get a plethora of different uses. It’s used in a sentence as a noun. It’s used in a sentence as a verb. It’s used in a sentence as a phrasal verb (with another element). It is implicit that the question, “what is the general meaning of the word ‘hammer’?” is nonsense—we search for what connects its different uses and we find only the different circumstances in which the word is used; we could say the noun “hammer” is the same word, in terms of its construction of letters, as the verb “hammer”; but is this different from saying that the word “sun” sounds the same as the word “son?” If someone unfamiliar with English were to ask me, in speech, what “sun/son” meant, I’d ask him what sense of the sound “son/sun” he meant. If he didn’t know what sense he meant, I’d give a few examples either by demonstrating the different semantics of the two words (by getting him to see how the two suns might be used correctly in different situations—i.e. a fiery ball in the sky / a male offspring) or I’d try to explain the syntactics of the two words (by using sentences that included the word “sun” and others that included the word “son”).
Similarly, we could say that a word such as “good” has the same visual-sound but different meanings. The different meanings depend on the circumstances in which the word is used. We can grasp a meaning only through a certain use of a word. To look for the essential characteristic of “good” (or any word) is to look for the general meaning of the word. But the meaning of a word depends on its use in a specific circumstance. To look for the “good” in general is to look for the same [sən] sound in the words “sun” and “son.” But what about the “concept” of the word “good?” Don’t we use phrases like “a good runner,” a “good person,” “a good day,” etc., as though “good” has the same meaning in each case (it does have the same syntactics). But, as Wittgenstein points out in his “Lecture on Ethics,” “good” is used relatively, and its semantics depend upon its use. What makes a “good runner” is exactly what does not make a “good swimmer” (and these are analogous examples of athletes). Try to abstract the general “good” from what makes a “good horse” and a “good cook.” What is left?
So we have to see how a word is used in the circumstances in which we wish to derive its meaning (or definition). The problem is that our language is insufficient: we use the same word differently in different situations, and what connects one of its meanings to another is, essentially, its appearance, or what Wittgenstein calls “family resemblances.” (Sometimes siblings look strikingly similar, other times it’s hard to imagine that they’re related; and sometimes the unrelated look identical.) But don’t we say that a “good something” points to a “best” of something, perhaps an “ideal something?” To this Wittgenstein’s “Lecture on Ethics” is also informative: what happens if we ask what the “best road to take to town is?” Well, it depends if we want the quickest path to town, or the most scenic, or the least busy, and so on. The circumstances determine what we would call the “best.”
So a definition of a word might mislead us, if we don’t know the sense in which a word or phrase has meaning? But, as J.L. Austin points out in his illuminating essay, “The Meaning of a Word” (1940),
“The sense in which a word or a phrase ‘has a meaning’ is derivative from the sense in which a sentence ‘has a meaning’: to say a word or a phrase ‘has a meaning’ is to say that there are sentences in which it occurs which ‘have meanings’: and to know the meaning which the word or phrase has, is to know the meaning of sentences in which it occurs” (p.56, Philosophical Papers, 1961).
His statement above should be consistent with our everyday experiences: when we encounter unfamiliar words in sentences, we either intuit the unknown word’s meaning in the sentence—from the sentence (if we can)—or look up the definition of the word in a dictionary to make sense of the sentence (if we can’t make sense of the sentence without knowing that word). Only after this step can you ask your question."All the dictionary can do when we "look up the meaning of a word" is to suggest aids to the understanding of sentences in which it occurs" ("The Meaning of a Word").