In our publications, we prefer to avoid an orphan—a word alone on a line or at the end of a paragraph—if the word, including any punctuation, is fewer than five characters (e.g., too.). We also prefer to avoid part of a word on a line by itself (e.g., sighted, if the full word is farsighted). An exception is made if Merriam-Webster includes the hyphen in the word (e.g., far-fetched).

Most publishers avoid widows, usually defined as a short line at the top of a page, but the MLA goes further: we don’t allow a line by itself —even a full line—at the top or bottom of a page. 

In general, student writers and scholars submitting manuscripts for publication need not be concerned about orphaned words or widowed lines since publishers, including the MLA, address this problem during the publication process. But in some cases scholars may have sole responsibility for checking page proofs, so understanding the conventions for orphans and widows may be helpful.