What is a Heteronym?

This book deals with the Heteronym, a word that has one spelling, but two different pronunciations and two separate meanings, like the titular "Sewer".  The Heteronym must on no account be confused with its remote relatives, the Synonym and the Homonym, which, since they only demand similarity of meaning or sound, are in easy and abundant supply.  The Heteronym, being itself extremely rare, complex, and difficult to discover, looks down on these others with the lofty disdain of an orchid contemplating a field of dandelions.
  
The Heteronym is present in English only because of the delightful pronunciation variability that our language can present to us.  The boringly regular Romance languages cannot so supply manage to supply such pairs.   Since discovering these odd couples, we have become obsessive in our quest.  This is a collection of some of our favorites, and we hope you will be content with its content.