Heteronyms are words that are spelled identically but have different meanings when pronounced differently. For example:
Lead, pronounced LEED, means to guide. However, lead, pronounced LED, means a metallic element.
Homographs are words that are spelled the same but differ in meaning, derivation, or pronunciation. Homophones are words that are pronounced the same but differ in meaning, derivation, or spelling. Homonyms are words that are spelled and pronounced the same but have different meanings. There is overlap among these categories. Heteronyms are specific types of homographs in which the different pronunciations are associated with different meanings. Many heteronyms are the result of one pronunciation being a verb and another being a noun.
Watch this video learn about the pronunciation of heteronyms and homophones