What are homonyms, homophones, and homographs?

Homonym can be troublesome because it may refer to three distinct classes of words. Homonyms may be words with identical pronunciations but different spellings and meanings, such as to, too, and two. Or they may be words with both identical pronunciations and identical spellings but different meanings, such as quail (the bird) and quail (to cringe). Finally, they may be words that are spelled alike but are different in pronunciation and meaning, such as the bow of a ship and bow that shoots arrows. The first and second types are sometimes called homophones, and the second and third types are sometimes called homographs—which makes naming the second type a bit confusing. Some language scholars prefer to limit homonym to the third type.