Portal:United States Government Publishing Office, U.S. Government Printing Office Style Manual (2008)
“ A compound word is a union of two or more words, either with or without a hyphen. It conveys a unit idea that is not as clearly or quickly conveyed by the component words in unconnected succession. The hyphen is a mark of punctuation that not only unites but separates the component words, and thus facilitates understanding, aids readability, and ensures correct pronunciation. When compound words must be divided at the end of a line, such division should be made leaving prefixes and combining forms of more than one syllable intact. ”
