Though it would make our lives simpler and fill our mornings with pleasant birdsong, there exists no one true definition of 'homonym.'  It is an easy affair to speculate why this is the case, but before we do so let us demonstrate the diversity of opinion.

Here is Miriam-Webster's definition.

homonym
1 a : HOMOPHONE b : HOMOGRAPH c : one of two or more words spelled and pronounced alike but different in meaning (as the noun quail and the verb to quail)

Notice the first definition given is that of 'homophone.'  Now here is the American Heritage Dictionary's version.

homonym
1. One of two or more words that have the same sound and often the same spelling but differ in meaning, such as bank (embankment) and bank (place where money is kept). 2a. A word used to designate several different things.

You'll notice that AHD is vague: same sound and *often* the same spelling.

And here is the Random House Unabridged Dictionary's definition.

homonym
1. homophone (def. 1). 2. a word the same as another in sound and spelling but different in meaning, as chase 'to pursue' and chase 'to ornament metal.'  3. (loosely) homograph.

Shall we, then, in the words of Mr. Hammer, break it down?

HOMOGRAPH
Little mystery here.  Homo- (from the Greek homos, meaning one and the same) and -graph (from the Greek graphos, something written or drawn).  Two words that are homographs are written the same, *regardless* of how they are pronounced.   Thus 'wind' (as in The Wind in the Willows) and 'wind' (as in, "Don't forget to wind your watch") are homographs and are pronounced differently, while 'bear' (as in, "I can't bear karaoke versions of New Wave hits") and 'bear' (as in, "There you are, Jerome—would you like to see a polar bear eat a seal?") are homographs and are pronounced identically.

(Please bear with us.)

HOMOPHONE
Similarly, a homophone is fairly straightforward.  Again, homo- (from the Greek homos, meaning one and the same) and -phone (from the Greek phone, voice).   Homophones are voiced—that is, pronounced—identically, *regardless* of spelling or meaning.  Thus 1) 'rays' (as in rays of the sun) and 'rays' (as in svelte aquatic animals) are homophones with identical spelling and distinct meanings, 2) 'rays' and 'raze' are homophones with distinct spellings and distinct meanings, and 3) 'gray' and 'grey' are homophones with distinct spellings and identical meanings.

HOMONYM
'Homonym' derives from the Greek word homonymon, which was a form of the word homonymos, from homo- ('identically') and -onymos ('named,' from onyma, 'name').  'Homonyms' are words with the same name.  And here, perhaps, is where the confusion arises.  Are words 'named' how they are written, or how they are pronounced?

Let's return to our previous orsine example. 'Bear' (the animal) and 'bear' (the burden) are homophones—they are pronounced identically, regardless of meaning and spelling. But they are also homographs: they are spelled identically, regardless of meaning and pronunciation.  Many people consider them 'homonyms.' Of course, many people consider fault lines to be good places to live.

But what about 'bear' (the burden) and 'bare' (your soul)?  These words are homophones—pronounced identically, regardless of other factors—but not homographs. Are they homonyms?

We say yes, and with feeling. In common usage a homonym may be a simple homophone or a simple homograph, or a homophone with special conditions (for example, same spelling and meaning). In fact, in common usage a homonym may be almost anything at all—as the above dictionary quotations suggest. We believe the confusion stems, again, from the question of 'name'—the onyma of a homonym.  Is the name written, or spoken, or both?

The homonyms we like are the homonyms we learned as children. They are the homonyms we now share: that limited and distinguished collection of English words pronounced identically but spelled differently, with different meanings. Two words with the same name, and yet—what stunning specificity! What maddening orthography! What more could one want?

Well, three words.