In typography, words that are spelled the same, but pronounced and hyphenated differently (e.g., in-val-id, in-va-lid; pre-sent, pres-ent). (Homonyms are those words that are only pronounced the same, e.g., "to" and "too.") The process of hyphenation in America is based upon pronunciation (in England, it's based on the word's derivation). Computer programs that hyphenate automatically cannot effectively handle homographs, because the computer would have to discern the meanings of the words. In any case, the hyphenation of these words depends upon the mind of the person who wrote them.